If anyone wants to check at the original RFD thread, there is now a way to use VoXalot in Conjuction with PBXes that makes callthru possible...
One could replace adding each Voip Provider at PBXes (as mentioned in the guide), with just adding your VoXalot account where you have dial plans configured.
In other words you can achieve CallThrough with SipBroker--VoXalot Acct(One Set up just for CallThru)--PBXes--VoXalot Account You use for all your Calling with Smart Call Configured
And even add TPad, so you can use their access Numbers for places where SipBroker does not offer local numbers.
Free DID Numbers, Free Voip Calls, & more Voip Info - RedFlagDeals.com Forums
Placing VoIP Calls from any Old Regular PSTN Phone