Google Sitemap Generator Filter Strangeness

Hi all,

I'm using the official Google Sitemap Generator to generate a sitemap by walking the filesystem (using a <directory> option in the config file).
I need a few filter rules to exclude a few files from being added to the sitemap. If I try this:

<filter  action="drop"  type="wildcard"  pattern="file.php"  />

Code (xml):

or

<filter  action="drop"  type="wildcard"  pattern="file*"  />

Code (xml):

or similar patterns it just doesn't do it. For some reason I have to do:

<filter  action="drop"  type="wildcard"  pattern="*file.php"  />

Code (xml):

or

<filter  action="drop"  type="wildcard"  pattern="*file*"  />

Code (xml):

Without the leading '*' it just doesn't take affect, which seems rather strange. Is anyone else seeing this behaviour or is there something strange going on?
I can see nothing in the docs to suggest that this behaviour is intentional...

Thanks in advance,
David.