Prime Infrastructure 1.2 Release note says:
Third Party Support
Ability to discover and monitor third-party (non-Cisco) switches that support RFC 1213 and wireless controllers/access points from Aruba Networks.
For the 5508, you're not going to see any support for 3rd party APs (like you can't convert third party capwap APs to talk to the WLC and use its configuration).
Prime Infrastructure appears to snmp manage third party controllers but the release note says Aruba....
The PI Configuration guide for this (http://www.cisco.com/en/US/docs/wireless/prime_infrastructure/1.2/configuration/guide/ctrlcfg.html#wp2565038) makes not reference to third party models though (as far as I can see)....