Multiple SIP registrations from same SIP Provider

Have things changed much in the revisions of 1.2 regarding this little problem?

I’ve found the asterisk SIP channels page on voip-info to be interesting - haven’t acted on it yet cos i’ve been mucking around with real-time and getting PHPeclipse to try and install.

Any experiences you can link me to or describe - will this change in 1.4 or is this a SIP thing?