Fading text

[bttf]

I'd like to display a text ("hello") at frame n. 350 that start fading and totally disappear at frame n. 500. I'd like to control size, font, color and position.
How can i do that ?
Really thanks.

[IanB]

...
A=Subtitle("Hello", X=20, Y=30, first_frame=350, last_frame=500, \
Font="Arial", Size=18, Text_color=$FFFF00 , halo_color=$000000)
A=A.Trim(0, 500)
B=Trim(350, 0)
Dissolve(A, B, 151)

[bttf]

Really thanks...