In that case, you might be able to use exactly the process I've defined.
The refer and oosp settings may just work out of the box, there are only 2 values for each (true/false) and the combinations control what type of transfer you do for either a 2 step, or 1 step transfer (a TRoute counts as 1 step), INVITE, REINVITE or REFER. You would need to experiment with what works best for your specific use case. In my case, we set refer-enabled = false and oosp-transfer = true, which means you get a REFER on a single step transfer, but an INVITE when doing a 2 step. How you set it will depend on how the interface to the outside world, assuming that'll be the OXE, reacts to each INVITE type. There's a table in the SIP Server deployment guide detailing which combinations get what results.
To configure it:
- Create a DN of type "Trunk Group DN" in your SIP Server switch. The number for this should be the exact number you need to dial from the SIP Server to go out through the Alcatel to the final destination.
- Set the contact option for that DN to be the SIP interface you would normally configure a trunk DN to point to.
- In your routing strategy, transfer to the number, then handle the red / green ports in IRD to do whatever you need them to.
It's pretty much as simple as that, let me know if you need any other info.
note: I did this with a Dialogic BN-2020 acting as an ISDN gateway, not an Alcatel so as soon as the config leaves Genesys I'll be of no help at all.