Pass parameter to radtreeview webservice

I am using the webservice method of populating my radtreeview as it was described as the most efficient way to load large amounts of data. So the signature of my webservice method is:

[WebMethod]
public RadTreeNodeData[] WebServiceMethodName(RadTreeNodeData node, object context)

However, the nodes that I am populating the tree with depend on the security access of the user that is logged in to my application..Is it possible to pass additional parameters to the webservice method? Or must I use a ServerSideCallBack method to p开发者_JS百科opulate the tree? I am hoping that I can still use the webservices functionality... I would like to pass a signature like this to my webservice method:

[WebMethod]
public RadTreeNodeData[] WebServiceMethodName(RadTreeNodeData node, object context, object userSession)   

Any ideas?

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I discovered that this has been answered in the telerik forums: http://www.telerik.com/community/forums/aspnet-ajax/treeview/pass-parameter-to-webservice-on-node-expand.aspx

The idea is to use the ClientNodePopulating event and inject the param in the context object.