Also note that you can tell LabVIEW (after a restart) to not use system decimals.
useLocaleDecimalPt=False in the ini file will tell LabVIEw to always use '.' as decimal separator.
There's an option for this in the options dialog as well, Options>Front Panel. I'm pretty sure it works on the diagram as well, so IMO this option should be in environment in stead.
I don't advice to use it, as the user preference should be respected. Also, peer programmer (or future you) might not have this option on and will be puzzled for sure. Installing (a new version of) LabVIEW will for instance not set this option by default.
The option can be a lifesaver if you got a LabVIEW application that was written by a less considerate programmer.
The option can also be great as a quick test to check if this is a problem in your own application. Obviously, a customer will be happy that it works with this hack, but if this option fixes a problem, you have a bug to fix.