Recursive Commandline MD5 tool

I have finally found a recursive commandline tool that actually works and puts out in the correct format! here:

code.kliu.org/misc/hashutils/

The syntax is like this
md5sum.exe -r file1.ext file2.ext folder*

So the problem is that for a complete folder calculation, you have to add * at the end of the folder name.

So somthing like this in DOpus doesn't work with folders
md5sum.exe -r {allfile$} > check.md5

Is there a way to tell DOpus if it's a folder to add a * to the end? The selection could be a combination of several files and folders.

I don't think there is any way to do that, without adding a script between Opus and the other program which adjusted the arguments to add * after ones which were folders.