£0.0 value donation gets a thankyou.

Firstly , thanks for the module, we're finding it useful for a large charity site we're working on.

I can probably hack the module to fix this, but thought i post it up. We haven't found a way to make the donation pane 'not required' , so have had to add a '0' zero amount to get around this. If the customer checks out with the zero amount donated , they get a message on their invoice saying:

£0.0 donated, thankyou !

Which at best sounds a bit sarcastic :-) Am i missing some options for making the donation non-required, or shall I get hacking?