ASP.NET UpdatePanel Time Out

I'm making a request from an UpdatePanel that takes more then 90 seconds. I'm getting this timeout error:

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerTimeoutException: The server request timed out.

Does anyone know if there is a way to increase the amount of time before the call times out?

There is a property on the ScriptManager which allows you to set the time-out in seconds. The default value is 90 seconds.

AsyncPostBackTimeout="300"

In my case the ScriptManager object was created in a Master Page file that was then shared with the Content Page files. So to change the ScriptManager.AsyncPostBackTimeout property in the Content Page, I had to access the object in the Content Page's aspx.cs file:

protected void Page_Load(object sender, EventArgs e)
{
     . . . 
     ScriptManager _scriptMan = ScriptManager.GetCurrent(this);
     _scriptMan.AsyncPostBackTimeout = 36000;
}