'auto-apt search' vs 'dpkg -L'

[Alec]

Hi

I noticed that (on woody) searching for a file with auto-apt will sometimes 
produce no results, while dpkg -L may list the file. E.g.
$ auto-apt search pa_sml
$ dpkg -L camlp4 | grep pa_sml
/usr/lib/camlp4/pa_sml.cmo

Why?

Thanks
Alec