POCO Queries...

It appears that the POCO implementation is a great way of allowing inclusion of short lists of items such as US states in queries, but there are often times when we need to return a subset of a large server side collection and we can't quite see how this would be done.
For example, we would like to return a collection of images where the filename begins with "A", so how would this be implemented?
The standard GetImageCollection() approach appears to have to read every single image into an IEnumerable collection so that the client can subsequently filter them, while the ideal would be to allow GetImageCollection(string myfilter) so the query can be "from img in ImageCollection("A*.*") select img".
I know it's not an ivory tower solution, but is there another way to approach this other than adding a custom webservice?
If we are forced to add the webservice, how can we leverage the existing security session?  When fetching data from SQL server it is passed the query, but the POCO example seems to assume that you return everything and filter afterwards.

Cheers,
 Jason

Would it be possible to also receive the query expression ?

I think you want to respect RIA standard.
Maybe you could have both RIA method, and a custom interface that allow us to receive the expression ?

Your POCO is a really nice feature.

Thanks Kim,
Yes, I guessed that the sets were filtered at the server end, but the idea of loading 20MB of images into a collection simply to let the server then check the filename is a huge overhead.
We are currently struggling with the undocumented InvokeServerMethodAsync method (did I also mention that there are no examples and it's undocumented? :) )

Cheers,
 Jason