I know this works on other Pa models. I can't seem to find any info on how to do this. I can't believe Korg would leave out such a basic feature like this - I'd rather believe I'm missing something. Any help would be appreciated.

On PA3X and PA900 there is a button labeled STS Mode. There are three selections. One, it automatically changes STS with variation. Two, it automatically selects the first STS when the style is loaded. Three, it is off; all selections done manually.
Toggle between selections by pressing the button.

STS button "solid light" it always picks sts #1 when you change to a new style ( stays on sts #1 even if you change to variation 2,3 or 4. STS button "light flashing" it will change to sts 1,2,3 or 4 depending on which variation you are using. STS button "no light" whatever sound you are using will stay that sound no matter what style or variation you are selecting.

Ah, er, umm - where exactly is that STS button on the Pa300?????

That's just it. There is no STS button. Only the STS 1, 2, 3, 4 buttons directly under the screen. They are used only to manually turn on the STS. So far I've found no way to automatically trigger the STS when triggering one of the four variation buttons. This is frustrating, KORG!

I think you are right. I looked through the manual and it makes no reference to the STS Modes. All it says is to press a button or the screen to select the STS you want.
Wouldn't bother me because I always use it that way anyway.

So the bottom line is - syncing STS to the Variation function cannot be accomplished on the Pa300 (although it can on all other Pa arrangers). I can learn to live without it - but it would be nice if KORG would add it somehow within the next software update.

Tim ... I guess there are some features they have to leave off the 300 to justify the price difference between that and the 600 ...

I am sorry! I have not purchased any of the PA300 models and thought it would have the same feature as the 600 and 900.

Interestingly enough, I HAVE been able to load some DNC voices into the Pa300 and they seem to work. Most don't. I found the "Concert Guitar DNC" sounds good, as does the "Soft Latin Sax DNC" - you can even get the gliss when you play intervals of 6,7,and 8. However, there's no dedicated control buttons to trigger DNC features.