Don't remember exactly but I think you can get to the valve by removing the passenger side airbag. There is a red connector in the footwell on the passenger side. Pull the carpet back from firewall and then remove the black false panel. Disconnecting this red plug disables airbag. There is a single bolt that holds the airbag assembly in place. Use a socket extension up through the bottom of dash knee bolster to remove this bolt. The pull airbag assembly out.

This is described on the CD under SRS. (suggest you read this because inadvertant airbag deployment is not pleasant)

You may also have to remove the knee bolster.

J. M. van Swaay