DI API Update UDFs in Production Order - Route Stage Rows

[Former Member]

I am trying to update UDFs for the Route Stage, I have created 8 UDFs and I cannot seem to access them to update the value.

var stId = pro.Lines.StageID;
if (stId != 0)
{
    pro.Stages.SetCurrentLine(stId - 1);
    // How to update the UDFs in the Stages
    // Fields UpdateDate, UpdateTime, UpdateBy, UpdateById
}

I get the Stage ID and am able to access the fields in the stage, but to access user fields in other tables I use

ProductionOrder.UserFields.Fields.Item("UdfName").Value, ther is no property UserFields in pro.Stages