Adding MIFs to books, and opening them as ASCII text

Hi, here are a couple of questions about working with MIF files in FrameMaker 12.

In the 'ADOBE FRAMEMAKER 12 MIF Reference" PDF, in Chpt. 2 (page 9), it says:

"If you use FrameMaker to edit a MIF file, you must prevent it from interpreting MIF statements when you open the

file by holding down a modifier key and clicking Open in the Open dialog box."  (in Windows, the Modifier Key is Control or Shift)... I can't seem to get this to work in Frame 12 - if I shift- or Control-click the File menu, it doesn't *have* an Open command. If I go via an Open dialog box, it doesn't take any notice of the shift or control key being held down. Is this broken in Frame 12, or am I doing it wrong?

Also, I am interested in adding MIF files to a book. (I'll tell you why in a minute but if I click the 'Add file' icon in the book pane, and select the MIF file and click open, I get a pop up dialogue saying:

"Add Non-Document File to Book:   

The file '<filename>.mif' is not in recognizable format.
Are you sure you want to add this file to '<bookname>.book'?"

I am not sure why it's generating this error - I can still click "Add" and it adds it OK and can open the MIF file fine. Is this a bug?

(It is a "<MIFFile 12.0>" generated from Frame12 itself, by the way).

The reason I am trying this is because I thought maybe I could install a copy of Frame12 on our software build server,

and check in my source files as MIFs. (Because they're ASCII files, the SVN version control will be able to show 'diffs' for my text changes).

The build server could then be scripted to run Frame from the command line, open the book with the MIF files, export them as CHMs and thus build our HTML Help during each nightly build, with the source all nicely under SVN source control.
... not sure if anyone has tried this before?