Filtering with more than 4 types (OSX)

[Éric Chatonet]

Bonjour à tous les Reveurs,

OSX 10.3
Rev 2.1.2

I want to display a dialog allowing the user to choose only pictures 
i.e BMP,MooV, JPEG, PNG, GIF and TIFF (cross platform app).
Only the four first types are considered:

answer file tPrompt with filter "MooVJPEGPNGfGIFfTIFFBMP " -- filters 
correctly MooV,JPEG,PNG and GIF while TIFF and BMP files are disabled
answer file tPrompt with filter "PNGfGIFfTIFFBMP MooVJPEG" -- filters 
correctly PNG, GIF, TIF and BMP while MooV and JPEG files are disabled

Any idea to by-pass this apparent limitation?

Mille mercis par avance !

Eric Chatonet