[Typo3-dev] unlinking / deleting files with t3lib_extfilefunc - help needed

[Rainer (Rene) Suthoelder]

hi!
how do i delete/unlink files from an extension upload dir (fe. 
/uploads/tx_myext) using the file deletion method of t3lib_extfilefunc?

the reason i want to use this method is the implied syslog feature which i 
would need to have.
but whenever i try to delete such a file i get "Target was not within your 
mountpoints! (111)" - which is of course true =:o)

so: how could i achieve my goal (without mounting such a dir)? is there a 
way to temporarily assign a mountpoint and if so: how?

any help appreciated,

rainer