Short answer is yes with a disclaimer. The disclaimer first: This requires testing and validation in your environment. A free answer given on a forum should not be considered gospel on this topic.
Back to the 'yes.' CUBE isn't relevant here since you're interworking between ISDN Q.SIG and SIP; CUBE is only involved when all call legs are IP (i.e. not POTS/ISDN to IP).
IOS natively translates the ITU Q.850 cause codes into the equivalent SIP 4XX response. For example, a Q.850 cause code of 17 (User Busy) would translate into a SIP 486 Busy Here. I do not recall CUCM's response when the INVITE message expires (at 180 seconds by default); it would be a 4XX reason though.
Additionally, you can tunnel the actual QSIG messages over the SIP connection to CUCM if you desire. This allows even more of the Q.SIG functionality to work (e.g. MWI, Path Replacement, etc) since CUCM gets to see the actual Q.SIG payload. Previously you needed to use MGCP for this to work. Note that this is a relatively new feature and should be tested exhaustively to avoid user-impacting bugs.
Please remember to rate helpful responses and identify helpful or correct answers.
