E1 Tools 9.1.5 XMLP: How to move the reference line to the back on a BI Publisher Line Graph?

Hello all, I've been working on some advanced charts using BI Publisher Microsoft Word Plugin Build 11.117.0.79.  The charts I'm doing extend beyond the basic capabilities of the Microsoft Word plugin, so I work directly with the XML/XPATH to define the graphs.  In my current example, I've set two reference lines to highlight performance metrics, but I can't for the life of me figure out how to send the reference lines to the background behind the data being plotted.  The rowdata lines and markers end up getting lost behind the reference lines.  This makes it a bit more difficult to