I think what he's saying is - they have a "mobile" field in their Active Directory that's populated and want this added to the directory.
What johnp is assuming is that each user has an additional "phone" configured in MiCollab which is configured as an "external hot desk" with their mobile entered as the "hot desk user external number".
When you provision your new users, you can use a template which has:
- a normal extension as their deskphone
- a secondary phone configured as "external hot desk" with "add to directory" ticked, and "derive DN" ticked.
What *I* would like to know is this: you can match up the AD field "mobile" to the MiCollab IDS field "mobile phone directory number", but how do you auto-populate the contents of "mobile" into the secondary phone that's in your user template?