It sounds like you want the DIR 615 to act just as a WAP?
For my wireless router I had to do the following:
Assign a LAN IP address to the router in it's config pages.
Turn off DHCP.
Disable NAT by adding a static route as:
Destination LAN IP - Blank
Subnet mask- Blank
Default Gateway - IP address of router
Hop count - 10 (Not sure about this number but 10 works for me)
Interface - LAN
Alternatively if you are feeling brave it looks like the DIR615 is compatible with DDRWT
From memory this will let you set up the router as a WAP.
Edit - Just noticed you are already running DDRWT
Edited by deleted (Sat 21-Jan-12 21:32:29)