[TYPO3] DAM extend categories

[Michael Paffrath]

hi!

ich want to build a galery using DAM.
most of the functions i need are already in DAM - one thing i want to
add is that you can "give" a category a thumbnail.
i could change the tca.php and the ext_tables.php to my needs, but
then i have to make these changes again when i update DAM ...

can anybody give me a hint how i could do that?

so long,
michael