issue resoled, I was using the 'ALWAYS ASK' method.
next question: Is there a way to secure SYMRDP, so if someone steels my phone, the can't acces RDP.
Normaly I wouldn't set passwords in the device for the RDP connections, but my passwords have a _ symbol in it, which is not present on the SYMRDP keyboard.
On my N97, I have to press the 'SYM' button for it, but when I do that, SYMRDP thinks I press the CANCEL button on the login screen.