Help! strange bttv problem

[Richard Kimber <rkimber@ntlworld.com>]

When I do make xconfig for the first time in a clean 2.4.22 tree I am
presented with the option to have support for BT848 video for linux
(having already said 'm' to the main Video for Linux and to I2C support). 
When I choose 'm' and save, an examination of .config shows there is no
reference to it.

Re-doing make xconfig then shows that option to be greyed out.

Is there useable BT848 support in 2.4.22? 

A Google search suggests there is a problem, but I can't find any
instructions about what to do that are simple enough for me to follow.

Help would be appreciated.

Thanks.
- Richard.