How to set Dial Plan

[petchpk]

My Project is now like this

NEC SV9100 ---Connected via SIP Trunk--- Unify x8 --- connected to Sip Trunk--- Sangoma PBXAct

So, I used Unify x8 as a central PBX,

Now SV 9100 can call to Unify x8
and X8 can call to Sangoma as well

But I would like to set Dial Plan to let sv9100 to call with sangoma Extension

How to set it?

Thank you so much in advance for every suggestions