Need help with Cisco Linksys SPA8000 and SPA8800 Gateway Dial Plan

Hey guys,

I'm trying to help connect an old 4 line analog PBX (Mitel SX20).

We're using a Cisco Linksys SPA8000 connected as a BYOD device, and have it working with an analog phone just fine.

Problem is, the PBX requires users to dial 9 to get an outside line (2nd dial tone) before dialing a number.

But when we dial 9, nothing happens. Also tried dial 9 then 10 digits... tried following with #... nothing.

We're not fully understanding the Cisco Dial Plan documentation and need some help (or other suggestions).

Does this sound like a Dial Plan issue? Or perhaps there something more we need to do to make the gateway's FXS ports talk nicely to the PBX's analog FXO ports?

Thanks in advance for any suggestions!