OWA2013 and foreign Connector

Hello,

New issue with OWA2013/Exchange2013

With Exchange 2010 we use to declare a foreign-connector using a non-smtp address TESTFAX:

With Outlook and OWA 2010 it was possible to send email to the foreign connecotr using the following syntax:

[TESTFAX:acustomstring] 

With Exchange 2013, the syntax [TESTFAX:acustomstring] is working fine with Outlook but not with OWA2013. It is blocked by the GUI that keeps saying the address is invalid.

Do you know if there is a new syntax in Exchange 2013 or OWA 2013.

Thanks

Lionel