Importing Leads with Umlaut in email Address not working

I am trying to import email addresses with Umlaut. However all email addresses with umlauts in them are flagged as invalid.

I checked my settings:
UTF-8 in SuiteCRM and the import file is coded in UTF-8 as well

Any help is appreciated.

Regards

Cedric

Please refer to these two articles to have a better understanding of valid email addresses:

http://en.wikipedia.org/wiki/E-mail_address#RFC_specification

http://social.technet.microsoft.com/Forums/exchange/en-US/69f393aa-d555-4f8f-bb16-c636a129fc25/what-are-valid-and-invalid-email-address-characters?forum=exchangesvradminlegacy

I am not sure whether umlaut is a valid character (we are talking of the local part, ie: the left side of the @ sign). In any case I would refarin from using it because you will find that many servers will reject thhem. Similarly many sites that do an email validation will also reject them so why take the risk?