[Voip.ms] Running multiple sub-accounts from the same IP address

If this has already been asked, I'll apologize in advance. I have an ATA and a softphone logged in from the same address, I can receive calls on both, but only make calls from the ATA, both are using toronto6.voip.ms I'd like to keep using toronto6, because I like the internal extension feature. Is it possible to keep it this way, or do I need to change the server for the softphone? (I've also tried changing the port number on the softphone but I haven't figured out which port numbers I need to be using) Cheers, EQ