[xsl] node returned from a user function is no longer a node??

["Bordeman, Chris" <Chris.Bordeman@xxxxxxxxxxxxxxxxx>]

Consider this variable and the function it calls:

<variable name="buyerfirstaddressnode"
select="fn:getfirstactiveaddressnode(buyer/Addresses)"/>

<xsl:function name="fn:getfirstactiveaddressnode">
  <xsl:param name="addresses"/>
  <xsl:if test="$addresses">
    <xsl:sequence select="addresses/Address[Sequence=1 and
IsActive=1]"/>
  </xsl:if>
</xsl:function>

Now, if I access $buyerfirstaddressnode/StreetName for instance, or any
other member, I get an EMPTY STRING.  However, if I simply output the
$buyerfirstaddressnode variable, I get a string that LOOKS like it
contains the address data I want.

So it seems that it's being converted to a string for some reason, so I
try to set the function's return type to as="node()" or as="element()"
(don't know the difference) but now the compiler seems to require an
object to always be returned, a case which I don't know how to handle
(returning () causes compiler complaint too).

Help please?

Chris