Omnia drops internet connection when calling

[Guest billbo]

If I have a 3G/UMTS Connection running on my Samsung Omnia and I receive a call or perform an outgoing call, the internet connection closes!

I know, that this is normal with 2G/GPRS connections, but it should not be with 3G connections.

I use german O2 network and it worked with the same account with other devices, so it must be an issue of the Omnia...

Any idea to solve this problem?

Thanks very much!