Periods versus comma's in VBA conditional formatting formulas

Hi,
My Windows country settings use a comma for decimal separation and a period for thousand separation.

When I use this code in VBA:

Range("A2").Formula = "=0.9"

I use a period in VBA. In excel translates it as =0,9

However, when I use this code:

Range("A2").FormatConditions.Add Type:=xlCellValue, Operator:=xlNotBetween, Formula1:="=0,9", Formula2:="=1,1"

I have to use a comma, or I will get a run-time error '5' : "Invalid procedure, call or argument"

How can I make my workbook work in European AND US settings in Windows?

Thanks for helping me out here...