asterisk users - Aug 2004 - Can I place calls to arbitrary sip uri address from windows messenger 5 ?

Hi,

I've sucessfully registered windows messenger to Asterisk and can talk to
other extensions cause they appear as being online.

But can I place a call to arbitrary SIP address (if I enter it to contacts
it appears as offline and don't get possibility to start voice or video
conversation) ?

Are there any other free softphones for windows that would support video
also (sip or iax) ?

What are other practical experiences using WM and Asterisk ?

Thanks in advance,

regards,

Robert.