[Tilt, TyTN II, MDA Vario III Accessories] evilc:
I am writing this article as I have an HTC Kaiser and want the ultimate active holder for my car.

Brodit do an active holder, but it is regular USB, not extUSB, and it is hard wired to a cigarette lighter connector, so you cannot access audio via the extUSB whilst your Kaiser is in the holder. Also, Brodit seem to have abandoned screwing on the block that holds the USB plug in favour of melting it on, so you can't easily replace the plug with an extUSB splitter as you could with the Hermes holder.

This method should work for pretty much any extUSB phone (or even ones with other connectors) but in my examples I will obviously show a Kaiser and a brodit holder.

You will need:

Your phone.

A very thin plastic bag.

A passive holder (Brodit item 848752 for a Kaiser) or a suitably butchered active one that had the wrong plug.

Some plastic granules (Such as these - not the exact ones I used, anything similar should do)

A hob, pan and water.

An audio splitter (Such as this ORA 3-in-1 splitter)

About 10 minutes spare.

Step 1 - Preparation

Start boiling the pan of water, remove battery from phone (Put cover back on), put the phone in the plastic bag with plastic covering the USB socket.

Put the plug of the audio splitter into the phone whilst the plastic bag is still on the phone. The plastic bag should go inside the usb socket between the plug and the socket (That's why it needs to be a thin plastic bag). This is to make sure you get no melted plastic on your phone or in the USB socket.

Put the phone in the passive holder (Still inside plastic bag - again, why it needs to be so thin) - for the mentioned Brodit holder and a kaiser, do not slide it all the way to the stop at the end, leave about 1cm gap.

Step 2 - Holding the plug in place

So now you have your phone in the holder, with the plug in the place it needs to be to meet the phone as it is slid in, you need to hold the plug in that place permanently. This is acheived with the plastic granules I mentioned - they can be melted and moulded into any shape.

Once the water has boiled, place some plastic granules in the boiling water. You want maybe the size of a matchbox. Melting too much is fine as you can always re-melt and re-use it later.

Once the plastic is melted, remove from boiling water. You should be able to handle it right away - start kneading it to get rid of air pockets etc.

Roll it into a sausage and wrap it around the holder and the USB plug of the audio splitter - push it up against the phone to make sure it moulds nicely to it's contours - squidge it around as much of the passive holder as you can to make sure it has plenty of grip. Work fast as it hardens as it cools. Do not worry about getting the surface too smooth or perfect at this stage as the plastic can be worked once dry with sandpaper, knives etc.

If you have melted too much plastic, you can always pull it off at this stage - too little would be much more problematic to sort out.

Once you are happy, wait for it to start hardening as it cools.

Step 3 - Touching up

The inside will harden before the outside. Once it is structurally sound, but the outside is still a bit soft, remove the phone from the holder.

The plastic bag will probably stick to the melted plastic a bit, but you should be able to pull it away, or just leve the plastic bag on there. While the melted plastic is still a bit soft on the outside, you will need to work it a bit (use your finger or a cocktail stick) - neatening it up around the usb socket and moulding it against the holder where you could not before because the phone was in the way.

It sounds complicated, but it isn't. I did it first try and in 5 minutes flat. If you fail, you can always use a hair dryer to soften up the plastic and try again.

Step 4 (Optional) - Aesthetics

As it stands, it doesn't look very good, but the plastic is workable with tools (Or the stuff I have is) - sand it, carve it into nice smooth lines with no creases, then paint it black.

Once you have that done, you have the ultimate Kaiser holder - It rotates, it lets the keyboard open, and as soon as you slide the phone in the holder, it connects USB, audio and power.

Problems:

I am not sure how the plastic would fare in a very hot car or if mounted in front of a vent and there was hot air blasting at it. I think melting temp starts at 60 degrees celcius though, so you would probably be OK and what's the worst that could happen?

If I use my audio splitter (The ORA 3-in-1 adapter) with my cigarette lighter to USB cable (I have an official HTC one) for power, I get "Alternator whine" coming out of the Kaiser audio - there is a high pitched noise which gets higher pitched as you accelerate. Only really noticable on quiet bits of music. This may be any one of the parts' fault, but for me, the solution was to get power from my Blaupunkt Hamburg car stereo, which has a USB port.