vbscript to duplicate directory tree

I'd like to have a vb script written to do the following: Variables (either specified in command line or in script itself) Source directory Destination directory Extensions A source tree (containing subdirectories) containing files will be crawled. Files will be copied which match the extensions specified and do NOT have a file in the same directory with the same name but a .txt extension and greater than 0 length. So - if I specify pdf and tif as extensions, and the directory has the following files [login to view URL] 1000 bytes [login to view URL] 1000 bytes [login to view URL] 1000 bytes [login to view URL] 1000 bytes [login to view URL] 1000 bytes [login to view URL] 1000 bytes [login to view URL] 0 bytes [login to view URL] 1000 bytes [login to view URL], [login to view URL], and [login to view URL] will all be copied to the destination directory but no other files.