are interface variables available with the "I want to alert on: Custom Interface Poller" option?

hi,

Are interface variables like ${N=SwisEntity;M=FullName} and ${N=SwisEntity;M=Caption} supposed to be available to the "I want to alert on: Custom Interface Poller" option when creating an Alert? Because I only see the variables populated when I select "I want to alert on Interface." They show up uninterpreted when custom interface poller is selected. I am using the SnmpTrap action.

thanks,