Instead of pointing your gateway's "Incoming calls Calling search space" to a CSS with your phones in, add a dummy partition and css only for the purpose of adding those digits e.g. CSS_INCOMINGCALLS & PAR_INCOMINGCALLS.
In this new partition, add a traslation pattern that will match all calls, and add 90 to the "Calling Party Prefix digits" parameter. And select the css with your phones in as the Calling search space.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...