How to add several licenses to one account with repotools?

Repotools' help (3.0.1.x) told me that it should be possible to assign several licenses to one user account.

http://publib.boulder.ibm.com/infocenter/clmhelp/v3r0m1/index.jsp?topic=%2Fcom.ibm.jazz.install.doc%2Ftopics%2Fr_repotools_importusers.html
--> "The format of the file is a comma separated list of userid, name, e-mail address, license id(s), and role name(s)."

But if I perform this command
>> repotools-jts -importUsers fromFile=users.csv repositoryURL=... adminUserId=... adminPassword=...
with users.csv
>> UserId, User Name, E-Mail Address, com.ibm.team.rtc.buildsystem
repotools overwrites the existing User data with the new license and removed the established one.

Okay, never mind I will add both, the new and the still existing one:
>> UserId, User Name, E-Mail Address, com.ibm.team.rtc.buildsystem, com.ibm.rqm.tester.floating
Now repotools interprets the last value as a Jazz group and presents an error message.

If I leave the last comma
>> UserId, User Name, E-Mail Address, com.ibm.team.rtc.buildsystem com.ibm.rqm.tester.floating
repotools pointed out that the license type "com.ibm.team.rtc.buildsystem com.ibm.rqm.tester.floating" is unknown.

I also tried many other variants to embrace the license types, for example:
>> UserId, User Name, E-mail Adress, ['{"com.ibm.team.rtc.buildsystem, com.ibm.rqm.tester.floating"}')
No, not at same time :) but I have not success.

I can't do this via GUI because this task has to be automated for an Enterprise solution with thousands of users.

Is anybody out there who can help?

Thanks, Markus

(P.S. Or did anybody know how to add licenses via REST API?)