i7500 1.6 SMS sending problem

Hello.

I have a Galaxy i7500, on which I just successfully installed Android Galaxo 1.6.3.4, turns out everything works a-ok except for one little thing: Text messages, and in particulary sending them.
I've tried to search the web and this forum for advice on the matter but with poor results.

So if anyone would care to share their thoughts & info on this matter, it would be much appreciated.