how to add save as-action when clicking on link

[arer]

how do I add save as-action for files that not are listed in general\application

I download map-files i lot and they are named .tif .tfw .tab The tif-files download automatically but the 2 others I have to right click save link as
I dont see the 2 file-types under the application-list so i cant change them there but can i add them manually

[DanRaisch]

See this KB article -- http://kb.mozillazine.org/File_types_an ... ad_actions