XML R function description

Hi,

I was wondering if there is a standard for R function description in XML (or 
any plain text) format.

Rd files are the closest thing I found, but they do not describe the 
argument (or return value) types.
The purpose would be to write a program to automate the creation of C# 
wrapper around any R function, but without the argument type Rd descriptions 
are useless.

Any clues...

thank you
Teodor Krastev