SPU format subtitles

we had a client request backup copies of a DVD we made for them ages ago, in DVD SP 1.x. The DVD had subtitles. I had forgotten that we authored that title in DVD SP, since all of our subsequent DVDs were done in Maestro, and I just sent them a DVD-R of the backup without looking at the contents closely. In any case, the subtitles are in .spu format and they don't know what to do with them. For the life of me, i can't remember how that worked in DVD SP 1.x, we did it so long ago.

Can someone here refresh my memory - was the SPU file a text file imported into the subtitle editor application, or was it the output of the subtitle editor?

When i'm back in the studio tomorrow i'm planning on taking a look at this to see if there's something we can do, but I'm hoping .spu was the file you fed into the editor, because that would at least give me a fighting chance of making this thing usable to someone.

now i know how archivists must feel...

thanks,

-perry