@GB14 to answer your question personally... No, I haven't tried this for gateways.   

 

But a thought... the new devices, i.e. gateways, likely have unique OIDs (most make/model of device have unique snmp OIDs).  If you haven't defined whatever that unique OID is, you'd need to add that so the OID value is classified when discovery detects it.  And of course that OID classifier would need to trigger the pattern to interrogate the device.   Its conceivable that the prior Aruba pattern may need to be tweaked too based on spec's of the newer gateway device.  

 My 2 cents, hope this helps?