Playing back instruments in VSL using MIDI note events is a totally different thing than trying to sync a plugin to the tempo of your host program.
Solution #1: If you want, you can put in your own MIDI note events onto a Finale track and use them to play the sounds in the SD3 plugin. (you will want to turn off “Follow Host’ in SD3 if you do this)
Solution #2: Alternatively you can drag SD3 grooves onto a Finale track and all the MIDI notes, etc. from that Groove should be available for playing, editing, etc. in Finale. The thing is that I don’t know is if Finale has the ability to sync to another DAW (really, SD3 is just another DAW that you want to sync to your DAW-which in this case is Finale). If you use my either of my two methods, SD3 will be just a sound source for your MIDI events like VSL is now. (you will want to turn off “Follow Host’ in SD3 if you do this method as well)
Solution #3: Use Rewire to send timing data from Finale to SD3. (you will want “Follow Host” to be ON in this scenario.
From what I understand, this is a Finale issue rather than an SD3 issue. Judging from what I’ve read, Finale itself does not send the timing information to needed for SD3 (or any other plugins) to sync with it. Every other DAW I’ve worked with sends this info. It maybe that Finale started out as a notation program rather than a sequencing program.
Again, I have not used Finale since the very first version (I worked for Coda Music Software in the late 1990’s when Finale was a baby 
so I’m just spitballing here and giving you a few things to try.
(I just saw that you use Digital Performer as well. SD3 should sync with that, no problem)
-mac
Cubase Pro, Korg Kronos, M-50, Hammond XK-1c, Toontrack SD3, EZBass w/lots of expansions, many VSL Vi's, Shreddage 3 everything, and shit-tons of FX plugins.
