The solution is soooo simple! I found it about a minute after I posted the reply above.

It's no use opening the cr2 to do this (which is what I've always done). You have to do it in Poser, not outside it. Too smart for my own good!

Just double-click the parameter dial to open the dialog, enter the value and save. The saved cr2 will retain that value.

I'd still like to know what that 'e-005' business is about.

mac