XSL "Mailto" parameter formatting

I am attempting to create my own XSL Stylesheet for an XML table. (The table is actually a "user defined table" residing on a dotnetnuke website).

Almost everything is working very well.  However, I can't seem to get the syntax/format correct for the mailto: tag for the user to click for more information.  I would like to include a couple of the record elements into the subject and the body of the email message automatically.  Here's what I have:

           <a>
              <xsl:attribute name="href">mailto:mail@fbctopeka.com?subject=<xsl:value-of select="udt:Name" />;?body=Hello, I would like to reserve a copy of <xsl:value-of select="udt:Name" /> by <xsl:value-of select="udt:Author"/>  for our small group.  Please let me know if this is available for our use.
              </xsl:attribute>...select this series...
            </a>

What happens here is that EVERYTHING is put on the subject line.  When I changed the "body" portion to:

?&body= Hello, I would like to reserve ...

VWD gives me an "expected ';' " error...which in turn kills my stylesheet when it renders.

Can anyone help me with this?  I'm admittedly a beginner with XSL stylesheets, so my "style" here could be all wrong.

btw, the page, if this helps is at: http://www.fbctopeka.com/Ministries/SmallGroups/SmallGroupCurriculum/RelationshipswithGod/tabid/166/language/en-US/Default.aspx