particle animation

is it possible to animate halo alpha over particle life on a particle trail in 2.5?
id really like for those trails to loose alpha over time and kinda dissapear but i have no idea how to do that.


this is for a commercial project. deadline is closing in and i need to get this goodlooking! please everybody! help is very much appreciated, i have tried this for so long but i am stuck, i cant do it.

This was an option in 2.49, by mapping a blend texture to the PAttr (or something like that), but I don’t think that anything equivalent is implemented in 2.5 yet.