It's a multi-part process, but it works. Here's how:
Here's the BibleSupport link for a tool called "STEP to RTF".
Here's the BibleSupport link for a tool abbreviated as "Tooltip Tool".
1. Run "STEP to RTF" and it creates a document in "rich text format" (that's what "rtf" stands for).
2. Run Tooltip and create a commentary.
This works for every STEP book you can find that I know of - and there are several awesome STEP tools that are old and hard to find. But if you can find them, they're just awesome. I happen to have three titles available for purchase. If interested, you can PM me.