RRLP - How?

Dear developers, I found that RRLP requests are possible within OsmoNITB. http://security.osmocom.org/trac/wiki/RRLP The popular Free Software implementations of the GSM network ​OpenBSC <http://openbsc.osmocom.org/> and ​OpenBTS <http://openbts.sourceforge.net/> both support RRLP inquiries to mobile phones And I found it's possible to acrivate some setting in OnmoNITB but how can I do the actual request? I cannot find anything in the user manual, vty manual or in the menu... Thanks in advance!