Hashtable case sensitivity weirdness

Hi i have found something wierd,

When adding to a hashtable its case sensitive, but if you export the
hashtable to xml and import it again, it becomes case insensitive, can
i stop this without having to convert case everywhere?

Here is an output of what I did:

PS C:\> $test=@{}
PS C:\> $test.add("one","1")
PS C:\> $test.add("onE","1")
Exception calling "Add" with "2" argument(s): "Item has already been
added. Key in dictionary: 'one' Key being added:
'onE'"
At line:1 char:10
+ $test.add( <<<< "onE","1")
PS C:\> $test

Name Value
---- -----
one 1


PS C:\>
PS C:\> $test | export-clixml test.xml
PS C:\> $test = import-clixml test.xml
PS C:\> $test.add("One","1")
PS C:\> $test.add("onE","1")
PS C:\> $test.add("one","1")
PS C:\> $test

Name Value
---- -----
one 1
One 1
onE 1


PS C:\>