Using SOUNDEX (or any function)

Can anyone tell me how to achieve the following in SubSonic 2.1?

SELECT f1,f2 FROM t1 WHERE SOUNDEX(f4) = SOUNDEX('some expression')

I've tried:

...Where("soundex(f4)").IsEqualTo("soundex('bla bla')")...

but it looks like SubSonic is trying to parse the IsEqualTo parameter

Any help would be appreciated

OK - solved this using an inline query!