98 Chevy Van - pass. air bag disable?

Just wondering if anyone knows a safe way to disable a passenger side airbag.  I have a customer who carries his dog in his cargo van and does not have a button to disable the passenger airbag.  Is there a safe way to do this?  I was initially considering disconnecting the battery, then just unplugging the unit under the dash, but I am not too familiar with them.  Any info would be much appreciated... thanks.

I have heard of a Company that sold Air Bag Switch, like for the Chev P.U. and others       ...............But I cannot remember WHO????!!!!!................Sorry, my Brain hurts

Have U tried Chev Parts Dept?? 

There was a Campaign Notice for Owners of Vehicles without Passenger Air Bag Switch

Thanks for the info.  I will check out our local Chevy dealer first.