Maybe it wasn't clear, but it is exactly the capture records that I want to copy from one sfvidcap file into another. These are the clip records, i.e. tape name, timecode of start of clip, length of clip etc.

As far as I know you can't combine. They're specific to the session and tape. Combining would be like taking two separate text files and putting them together, "end of file" command and all: At best, you'd only have the first part read (because you'd hit the EOF), at wost nothing would work.

You'd have to redo the capture on the session again the way you want.

The Veggie Toolkit extensions used to do some juggling like this but the tools are no longer in production. The basic idea of it's batch capture tool was that it could read a text capture log (like you might have written down during a shoot or later when selecting footage from a window dub) and then import it to the timeline (or project) as if it was a series of offline clips. From there you could recapture your offline media.

You should be able to do a similar thing if you happen to have your actual video files, or maybe if you have them listed in a project as offline media. Once they're listed in a project you can close Vegas, go to the media files' folders, rename the folders, open Vegas again, and hopefully they'll be offline (As long as the veg file isn't in the same folder as the media this should work). From there you can recapture offline media and Vegas should load them all into the same sfvidcap file. It'll act like you want to do a batch capture but you don't actually have to go through with the capture. After they're entered into the SFVidcap file you can select them, right click them, and remove them from Batch Capture, which amounts to just unmarking them.

The key to getting the offline media into the right SFVidcap file is to either already have it open or to make sure it was the last SFVidcap file you opened.

<EDIT>
ANOTHER way to skin this cat is that if you still have all your media online you can open the SFVidcap file you want to copy FROM, select all the media, right-click, and select "Add to project media list." That will get all the clips into your project. From there you can go through the same dance moves to trick Vegas into marking them offline, and then recapture them into the correct file.
</EDIT>

Rob