Problem with renaming titles


I am currently testing the PDFCreator on my new Terminal Services Server and stuck with file rename. The software I'm printing documents from puts to the title path to the file where the \ (backslash) is substituted with _ (underline) as in following example:
where "E_NAS_Other_files_" is path to the folder. I would like to get rid of this part, but it does not work, probably _ (underline) is some special character. I can rename part of the path, for example get rid of "Other" but the _ character remains a problem.
Is there a way I could get rid of the full string?

Best regards

I have just found a solution with regex ->
Search for: .*(?=Z)
replace with nothing

After a bit more testing I'm not satisfied with this solution. Sometimes I have some other pattern which is also some other patterns, and the regex removes it, although I would like to keep or modify them in different way. I have following examples:

I would like to change to

I would like to change to

I would like to change to:

Any idea how I can solve it?