About the randomword,
I could add a session key, but i will have to save the session in the view to obtain a key (before the view is fully processed).
Then, i could clear the session when i get notified of the status by ogone (notify handler).
I am not sure if it clears out the values set by other offsite integration.

This can be implemented by the integrator himself, like using a (customer number + item number) value for orderID.