Fade filter not fading

[Wilson]

Hi im making a map and when a unit enters a region it fades to a custom fade filter........ i went to the 'World Edit Tutorials' and copyed everything they say to do.... Resize...... change format to .tga then to .blp
but in the game it doesnt fade, it fades when i use a .tga but thats huge and it doesnt work with .blp........
Is there ne reason y???