Relative paths or variables for use in bookmarks

Hi All,

just about to create a portable document library using FFP as viewer.
The content should walk with the browser: created a doc folder inside ":\PortableApps\DocuFoxPortable\Data\"
(* "DocuFoxPortable" = the re-named FFP folder)

all bookmarks for files in local storage get added with absolute path
"file:///--DriveLetter--:/PortableApps/..."
When changing them manually to "file:///Data/DocuFoxFiles/--Filename--" the files don't get found

Is there a way to access the file by relative links?
Thought this could be based on FFP app location: "--DriveLetter--:\PortableApps\DocuFoxPortable\FirefoxPortable.exe"
Bookmark now should be like "file:///Data/DocuFoxFiles/" to have a working link no matter from which volume/path the browser was started.

Option would be to set and use a variable like "set dfp_files --current dir--\Data\DocuFoxFiles" and then use "%dfp_files%" as "root path" in bookmarks.

Does any one have an idea how to implement rel. paths with FFP bookmarks? ^^

Warm Regards, JeS