Bug in 7.0.178? autocmd BufReadCmd * DoSomething expand("") fails if the filename contains %

[Thomas]

Hi,

I have the following line in my source:
exec 'autocmd BufReadCmd  '. pattern .' call '. rcmd .'(1,
expand("<afile>"), "", "%")'

This fails if the filename contains % which is replaced with
expand('%'). I can't seem to escape the % at any point, can I? Wrapping 
the exand("<afile>") in a escape(<>, "%") doesn't help.

Regards,
Thomas.