Opening a Drawing as READ ONLY from the Command Line?

[thenov]

I am writing a macro and need to open a dwg (from the command line with filedia off) as read only. The problem is I can NOT find how to do this as read only mode from the command line. I know you can click READ ONLY in the File Open Dialog box. But how do you do this from the command line when the fileida is truned off? Any help with this would be greatly appreciated.