Removing extension from Avaya and putting it on CUCM (Migration)

Hey all,
So I made a previous post about slow migrating from AVAYA to Cisco. We managed to get everything working without touching the config on the AVAYA G650. Our two T1 PRI are now plugged into the Cisco ISRs We added an intermediary ISR to plug in to the AVAYA system so the AVAYA system works as it always has. The intermediary ISR talks to CUCM via the lan. We configured everything on CUCM and almost everything works.

What we are having trouble with is getting the Avaya system to call the Cisco system after we remove an extension from Avaya. It doesn't even attempt to make the call. We get the instant busy signal from the station we are trying to call from. None of us are Avaya folks so we are at a loss of how to proceed.

For example,

extension 6100 was on the Avaya. We removed the station from the Avaya and put it on the Cisco. Now when we call the extension from an Avaya phone, no attempt to connect is made. We played around with route patterns and aar analysis on the Avaya but we dont want to break anything.

The only way we can currently get it to work is dial 9 and the full number to call from Cisco to Avaya. Any suggestions?