Exchange2013: ms-Exch-SMTP-Accept-Any-Sender not working with FrontendTransport

Hi everybody,

we are implementing a MX Exchange 2013 (CU 2) as the first Exchange server in the organization.

A ReceiveConnector for connections from our LAN network should allow authenticated users to send mails as any sender string. The solution I found here and elsewhere on the net seems to be simple:

Add-ADPermission -identity smtp-lan-relay -user "nt-autorität\anonymous-anmeldung" -extendedrights "ms-Exch-SMTP-Accept-Any-Sender"
Add-ADPermission -identity smtp-lan-relay -user "nt-autorität\anonymous-anmeldung" -extendedrights "ms-Exch-SMTP-Accept-Authoritative-Domain-Sender"

Unfortunately it is not working with FrontendTransports!
If I delete the connector and set it up as HubTransport it works!

Now my questions:

• is that a known issue / bug or a wanted behaviour?
• is there any disadvantage if I am running the connector as Hubtransport instead of FrontendTransport (as it should be)?

Thanks a lot for your help!