I have the Group Type option of "SIP" when adding a Trk group and also in the Signal group. However when listing the "system capacity" I have no SIP trunk licenses. Can I purchase SIP licenses and install SIP trunks out to external Adjuncts?
I was always told that you had to have the external SIP server in order to create SIP trunks?

Yes you need licenses but trunking is free on the CM platform. If you are trunking Avaya CM to Avaya CM then I would use H.323 trunks as they are very easy to set up. Check out this link if you must have SIP.

https://support.avaya.com/elmodocs2/sip/245206_5_1.pdf

Yea we do use h.323 trunking CM to CM, and also CM to Cisco Call Manager. But I have one group that has a VRU type device that wants to communicate with SIP to the Avaya CM. I was hoping to build a SIP trunk direcdtly to their server without having to use the middleware SIP server.

You will probably need the SIP server but I have only breezed through the SIP docs. It is so new that not many people are doing it. Good luck and let me know how you make out.