How to Post Sales Order through Web Services In NAV?

Hi Experts,

Can anyone provide me a link or guide me to post a sale order through web service.
I have created a simple application in Visual C# where i have provide a textbox and a button. Now i have a codeunit in NAV where a fucntion is written which take an sale order no as a parameter and post it. this code unit is published as a web service.

Now when i enter the oder no in a text box of a c# program I get an error which on research i found tht web services cannot handle user-Input(this is because whn we post sales order we get a srtmenu whc requires user interaction).

Can ayone help me to solve my problem.

thanks.