I created two files in the App_GlobalResources folder:
SiteResources.en-US.resx
SiteResources.sp-SP.resx
Both contain a value for "SiteTitleSeparator".
Here is what I am trying to do (The following line always returns null):
string sep = (string)GetGlobalResourceObject("SiteResources", "SiteTitle");
Note, that the Culture property on the page is set.
Answers in both VB and C# will be welcomed.
I changed the name of SiteResources.en-US.resx to SiteResources.resx and now everything works just fine.
Seems theer must be one invariant resource.