Converting subtitles to subpictures for Scenarist

[Fotis_Greece]

Ok, so far I have used the burn-on-the-movie method for adding subtitles to a film. What I want to do is simple. I want to convert my substation alpha subtitles to pictures-subpictures for use with Scenarist so as I can have the option of turning off the subtitles.
I know Scenarist accepts subpictures as subtiltes along with a .sst file which tells the software what picture goes to what timing. (if I am wrong please correct me).

Is there anyway to create these subpictures out of a subtitle file? And what specifications should these pictures have to fit Pal 4:3 or 16:9 dvds.

Thanks in advance

[smiller667]

I have no experience with Scenarist, but the one application you want is MaestroSBT. Converts SSA to various bmp-based formats plus script, including Scenarist.
Doom9 has a guide on Scenarist subtitles, and the MaestroSBT package comes with a doc containing some relevant info as well.