PackingSlip Problem

Hi. I don't get any answers on the forum so I thought I'll ask here aswell.
I'm trying to add a package slip.
I did have it working on the 1.5.4 development version, then I merged my branch with the 1.5.5.0 development branch. And accidentally removed the slip. Now I have re-added it using the exact same code from by old commits.
But I don't get any slip. I get a blank window.
So I added some "nice" debug code. Invoice works fine and looks like this:

**HTMLTemplateInvoice
HTMLTemplateInvoice is at class
Works?
Broken!?
Warning: Cannot modify header information - headers already sent...**


So it works. The last warning is because it try to send pdf but i already printed header due to debug.
However on my PackingSlip i only get this.


**HTMLTemplatePackageSlip
There is no class today
Works?**

So it fails in the getTemplateObject function. For some reason, it does not get loaded as class.
And I just can't see why.