Hi Romel
Do you have the GPS sync or non-sync connectorised radio?
The non-sync radio uses the Canopy pin out, which would be +V = 7/8 and return -V = 4/5. You would thus need to reverse the polarity when powering from your standard injector.
The GPS sync variant is 802.3af compliant, so it should work with your standard poinouts, as well as Cambium's Canopy pinout.
You could check out this guide:
http://community.cambiumnetworks.com/t5/ePMP-Installation/ePMP-PoE-Powering-Primer/td-p/49944
-Kyle