You are quite right saying that both Microsoft have used the decimal separator to "," and thousands separator " " for currency.
However this is only true for Windows 7 previous versions (Vista, XP and 2000) use decimal separator to "." and thousands separator ",". See National Language Support (NLS) API Reference http://msdn.microsoft.com/en-us/goglobal/bb896001.aspx
With IBM you reference Lotus Notes Forms version 3.5.1 which specifies the decimal separator to "," and thousands separator " " for currency. The documentation for Verion 3 of Lotus Notes specifies the decimal separator to "." and thousands separator "," for currency.
So basically someone changed it somewhere and the rest of us in South Africa appear to be none the wiser :)
I appreciate that you are unable to make any changes until I can provide a standardised source for the formatting. I will need to investigate why a change was made.
Thank you for your assistance.