I would suggest that you research your issue for a better solution. WEP is like not even having security at all (cracked back in 2001, and pretty much any smart-phone today can crack it in minutes with free software).
WEP - unsecure and deprecated.
WPA - people know how to bypass it (LOTS OF PEOPLE).
WPA2- less people know how to bypass it.
WPA-PSK (Pre-shared key) mode.
I have been using WPA2 for a number of years now (2006/07). Suggest you specifically look into WPA-PSK (Pre-shared key) mode (means all devices connecting to your WiFi would use the same 256-bit key generated from a password or passphrase. Provided your WiFi Router supports this (mandatory for all device since 2006), the Razr M should work seamlessly.