Various C code suffixes

[Shenderovich, Uri]

Hi , 
We have to port C code from some ancient OS and all the source has the
suffix *.x28 instead of something more conventional.
I didn't succeed to configure the Kdevelop (1.0 and 1.0beta1) to work with
these files,which means, that Kdevelop understands that it's a C source file
and treat it accordingly , but instead of adding it to the 'Sources' it adds
it to the 'Other'.

So, the question is there any remedy to handle the situation ? 

Thanks a lot , 
Uri