acidrip x264 strangness

[Ben Edwards]

I have been playing around with x264 in acidrip as it is supposed to
give better results to xvid (although encoding time is longer).  

When I select x264 a lot of the option boxes are greyed out, well almost
all in fact.  The strangest thing is it is no longer possible to set a
target file size of a bit-rate!  It also does not allow the number of
passes to be set.  Basically all you can use is the defaults ;(.

Any idea what is going on?

Ben