Patch for several output files sharing the same mime-type + proposal

[lasconic]

I'm evaluating lifeguard to run a EC2 conversion service with one file
as input and many files as output with different mime types.
For one mime-type, I got several files and apparently the code has
some bugs in that case. So I fixed it.
Find a patch at: http://dl.dropbox.com/u/497455/lifeguard/AbstractBaseService.java.patch

The patch keeps the previous implemented behavior. But I wonder if it
can be made better.
Currently, if you pass file.png as a key, and you got one file, you
get "file.png" but if you have 2 files you got 0file.png and
1file.png.
I would prefer something with wildcard:
For example for several pngs, passing file%.png as the key, you get
file0.png, file1.png etc...
What do you think? If I provide a patch, it will be included?

Lasconic