RAS Incoming Connections

I'm trying to add my XPe image the functionality of accepting incoming (and
outgoing) connections via serial port. I'm able to start the New Connection
Wizard, and create the connection (Connect direct to another computer ->
(as) Host -> COM1). An incomming connection icon is now placed in the
Network Connections. But when I right click the icon and choose Properties,
it says that "No hardware capable of accepting calls is installed".

What did I missed?
- Network is running. Communication with other network members via TCP/IP is
no problem.
- Com port is working. I can exchange (send and receive) data with another
computer directly connected via serial cable.
- I included the following components
RAS:
"Dial-up Client for Windows"
"Dial-Up Networking Common Libraries"
"Primitive: Rasman"
"Remote Access Monitory"
"IP Router Monitor Library"

RRAS:
"Dial-up Server for Windows" (better use hotfix Q318138)
"Internet Protocol Network Address Translation"
"Internet Authentication Service (IAS) and Remote Access Common Files
"Network Routing"
"Routing Common Files"
"Routing Table Library"
"Connection Manager Runtime"
"Phone & Modem Control Panel"
"Primitive: Tapi32"
"TAPI User Interface"

Additional:
"RAS Async adapter"
"WAN Miniport"
"Primitive: Mpr"

Would be thankful for any idea!

Kind regards, Christian