One of the things that is often asked is how can you call a certain lookup’s “Popup event” from code in the SalesLogix web client.  The SalesLogix web uses JavaScript to launch these lookups.  You can see the invoke code of the JavaScript by putting your cursor over the lookup’s button.  Once you know that syntax you can determine the server side code you would use to invoke the client side code.  The code will typically look like this:

ScriptManager.RegisterClientScriptBlock(this, GetType(), "ShowLookup","$(document).ready(function() { setTimeout(function() { " + AssignTo.ClientID + "_luobj.show() }, 500) })",true);

The important thing here is to change the red part of the code to be the server side control ID of the lookup you wish to pop.