Allow specific file types via wild cards in the command-line

I apologize in advance if this has been asked before.

I am building from the command line, and I want to include in my NewVersion.xml file a Folder element that tells the builder to include all files of a specific type (i.e. extension) from a given folder. For example, my file might contain the following snippet:

<Files dir="basedir"> <!-- Custom files --> <Folder source="\Releases\Custom\*.dll" insideonly="true"/>

When I try this, I get the error that the folder doesn't exist.

I realize that I could either specify the files explicitly or set up my build/update process to copy the *.dll files into their own folder and then use that as my source in the NewVersion.xml file. However, it would be a great deal simpler if I could simply ask for all the files that match my pattern (*.dll) in a folder.

Assuming that I haven't made a major boo-boo in my .xml file and this behavior isn't currently supported, is such a feature in the works for a future release?