How to convert a C# .Net dictionary object to an IData document?

I am not sure if this question goes here but just wanted to give it a shot.

I have a WSD in webMethods which i am trying to consume in C#. The input to this web service is an empty input document called Doc A and the output document is called Doc B, which is also an empty document.

The requirement is that the calling application will post bunch of key\value pairs in Doc A and WM will extract the key\values and do some processing based on the inputs.

I have created a dictionary in the C# class with the key\value pairs for the input but i do not understand how to send this dictionary in the input document for the WSD. What is a document in webMethods represented in .NET? An Array or List or Collection or a Dictionary?

Any pointers to this will be greatly appreciated.

var ws = new applicationOperations.applicationOperations();

            applicationOperations.IPPSCommonHeaderDoc wsInput = new applicationOperations.IPPSCommonHeaderDoc();

            wsInput.appName = "";
            wsInput.operation =;
            wsInput.tableName = "";
            wsInput.multipleRecordsOperator = applicationOperations.multipleRecordsOperator.Item;

            Dictionary<String,String> dictionary = new Dictionary<string,string>();

            applicationOperations.whereConditionKeyValues keyValues = new applicationOperations.whereConditionKeyValues();

            dictionary = keyValues; // this is where it errors out
//Error    1    Cannot implicitly convert type 'WebApplication1.applicationOperations.whereConditionKeyValues' to 'System.Collections.Generic.Dictionary<string,string>'

Input structure screen shot: