Researching RPC calls of mspdbsrv - visual-studio-2010

Question

mspdbsrv.exe is a utility used internally by Microsoft to update PDB files.
The compiler sends symbols updates to mspdbsrv through RPC, and mspdbsrv in turn updates the PDB file.
I'm trying to understand how these updates look like. unfortunately Microsoft did not release the IDL so I don't know the RPC function prototype, nevertheless looking at these updates as raw data is interesting enough.
Here is what I had in mind:
mspdbsrv.exe default endpoint in this case is \RPC Control\mspdb_10.00.30319.01_rtl_32_00000000000733A0. But mspdbsrv has a command line argument -endpoint that sets its endpoint to a different endpoint. The compiler however is probably always connecting to the default endpoint.
I suppose I could create a kind of "Proxy Server" that listens on mspdbsrv default endpoint, run mspdbsrv.exe with a different endpoint, and pass through the RPC to mspdbsrv transparently while logging it. The compiler will not know it is connected to the proxy since the proxy exposes the mspdbsrv endpoint.
Does this make sense? How can I write such proxy RPC server, without IDL?
Perhaps there is a shortcut if someone knows some details about these PDB updates?
Update
I've Found out what's the 00000000000733A0 suffix of mspdbsrv port name...(mspdb_10.00.30319.01_rtl_32_00000000000733A0).
This is the security access token of the current user!
Here is a snippet of how to obtain it:
HANDLE hToken;
if (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken) != 0)
{
TOKEN_STATISTICS tsStats;
DWORD dwOutSize;
if (GetTokenInformation(hToken, TokenStatistics, &tsStats, sizeof(tsStats), &dwOutSize))
{
printf(TEXT("%08x%08x\n"), (UINT)tsStats.AuthenticationId.HighPart, (UINT)tsStats.AuthenticationId.LowPart);
}
}