I successfully tested an outbound call to SIP.

Dial 522 to reach sip:7344375555@in.voipwelcome.com

The test call was from a Reseller Beta account, to my VOIPo account.
The same call direct dialed has some odd issue that sends it straight to VM.
This is a good work-around while this mystery remains. [#FEA-537016]

A Beta account to Beta account direct dialed made calls successfully to each other.
I also tried a sip routing shortcut, and that worked fine too
(Same format as shown above.)