blender 2.7x / how would i animate halo size and alpha across particle lifetime?

Hi there,

I started a new little animation project for my son, which includes a shot of a ufo approaching a planet.
For the beam of the ufo engines i planned to use particle systems just like i did in former blender days:

blender internal renderer

create a particle spawning halos

animate size and alpha over particel lifetime

the problem is the last step… even if i get the particle lifetime and age information using nodes,
the halo material alpha doesn’t seem to get influenced…

–> how would i animate the halo size over the particle lifetime?

thanks for your input !
regards
defstone

found exactly what i was looking for here:

happy blending
defstone