Do you want the log or do you just want to know who has been assigned a CAL and what type(s)?
For the latter there is a simple trick:
Add PgoAsXmlAlso=1 to the [Settings 7] section of C:\ProgramData\QlikTech\QlikViewServer\settings.ini and save the file.
Restart the QVS service (use services.msc to do this)
Start QV Desktop and create a new document. In your load script, import DocumentRoot\CalData.pgo.xml as xml. Replace DocumentRoot with the path to the location of the pgo files.
Create a few tables to view users, CALs and counts
