After several searches and trying out different solutions, I give up.

I got a typical menu;

- Main 1 (hardcoded)
- Main 2
  ------ sub 1
  ------ sub 2
  ------ sub 3
- Main 3
- Main 4

I've gotten it to show the Main and the sub menu fine, with the added class="selected" depending on what node you're on.

My submenu however, dissapears whenever I enter one of the sub pages.

My Content structure is as follows:

Primary node, the frontpage (1)
  ------ Textpage (2)
  ------------ Textpage (3)
  ------------ Textpage (3)
  ------ Textpage (2)
  ------ Textpage (2)

Here's the XSLT:

<!-- Main menu -->
  <ul id="menu">
    <li>
      <a href="/">
    <xsl:if test="$currentPage/@id = 1050">
      <xsl:attribute name="class">selected</xsl:attribute>
    </xsl:if>
      Forside      
      </a>
    </li>
  <xsl:for-each select="$currentPage/ancestor-or-self::* [@isDoc and @level=1]/* [@isDoc and string(umbracoNaviHide) != '1']">
    <xsl:sort select="@sortOrder" order="ascending"/>
    <li> |
      <a href="{umbraco.library:NiceUrl(current()/@id)}">
      <xsl:if test="$currentPage/ancestor-or-self::*/@id = current()/@id">
        <xsl:attribute name="class">selected</xsl:attribute>
      </xsl:if>
      <xsl:value-of select="current()/@nodeName"/>
      </a>    
    </li>
  </xsl:for-each>
  </ul>
<!-- Sub menu -->
  <xsl:if test="count($currentPage/* [@level=3]/*) &gt; 0">
  <ul id="subMenu">
  <xsl:for-each select="$currentPage/ancestor-or-self::* [@isDoc and @level=2]/* [@isDoc and string(umbracoNaviHide) != '1']">
    <xsl:sort select="@sortOrder" order="ascending"/>
    <li> <xsl:if test="position() != 1"> | </xsl:if>
      <a href="{umbraco.library:NiceUrl(current()/@id)}">
      <xsl:if test="$currentPage/ancestor-or-self::*/@id = current()/@id">
        <xsl:attribute name="class">selected</xsl:attribute>
      </xsl:if>
      <xsl:value-of select="current()/@nodeName"/>
      </a>    
    </li>
  </xsl:for-each>
  </ul>
  </xsl:if>

I also attempted doing the menu in Razor, but that went even worse, so I went with what I knew some of.

// Lars