SetSystemVariable has no effect

[FrankLenoir]

The value of InsertUnits in a drawing is millimeters and I want to set it to meters.
I have tried two techniques:
{code}.Application.SetSystemVariable("INSUNITS", 6){code}
and
{code}.Database.Insunits = UnitsValue.Meters{code}
When directly after setting the system variable is read back, it still has the value millimeters.
I have the same problem with other system variables. I use AutoCAD 2010 and VB 2008 express.
Does anyone recognizes this problem?

Thanks for any help

[fieldguy]

I hit this problem again today - once too often.  I found a post from Tony T (http://forums.autodesk.com/t5/NET/Set-Current-Lineweight/m-p/2582292/highlight/true#M16414) that worked again, this time for IMAGEFRAME.  I want IMAGEFRAME = 2 in a long list of files.  I am using CommandFlags.Session, and acmgd from Acad 2010.  I figured I should post here because of the topic title.  I know I will have to search it again. 

Application.SetSystemVariable("IMAGEFRAME", System.Convert.ToInt16(2))