Enabling natting on WinCE 5.0 device

[giovanni...@gmail.com]

Hello everybody,
I know that I'm posting a question related to a quite old platform, but any help will be appreciated.
Here is my configuration.

PC1 PC2 with GPRS connection (running WinCE 5.0)
192.168.0.40 IP address on ethernet port: 192.168.0.1
IP address on GPRS interface: X.X.X.X (name GPRSShared)


I would like to allow the PC1 to connect to a host via GPRS connection.
In order to do that I configured the gateway of PC1 as 192.168.0.1 and on the WinCE5.0 PC2 I setup up the following registry key:

HKEY_LOCAL_MACHINE\Comm\Tcpip\Parms\IpEnableRouter to 1.
HKEY_LOCAL_MACHINE\Comm\ConnectionSharing\EnableAddressTranslation 1
HKEY_LOCAL_MACHINE\Comm\ConnectionSharing\PublicInterface "GPRSShared"


Furthermore I have the following

desiredHostAddress 255.255.255.255 "GPRS ip address" "GPRS ip address"


where
desiredHostAddress

is an ip address that I would like to reach on the public network.

However at present time I'm not able to connect to the host desiredHostAddress from the PC1.

I don't understad if I have to setup something different on the PC2.
In the page http://msdn.microsoft.com/en-us/library/ms883134.aspx there is a reference to port mapping, however I don't understan if the things that I performed suffices in order to make it work, or if I have to specify something more.
Any reference to source code, examples and so on will be appreciated