menu position problem with IE

[KaiMartin]

After some tweaking I came up with a rather simple style that still suits my needs.  A vertical CSS menu is placed on the left with a square logo attached to the top. The menu should stay in place if the content is scrolled down. I slightly modified the default theme of CMSMS to achieve the desired behaviour. See: http://lilalaser.de/lila/index.php/english

The CSS code snippet for the menu:
/* NAV BAR ON THE LEFT AND ONE COLUMN OF CONTENT */
    div#content {
        position: relative;
        width: 100%;
        margin: 1.5em auto 2em auto;
        padding: 0;
        text-align: left;
    }
    div#main {
        float: left;
        margin-right: 1em;  /*--*/
        margin-left: 9em;  /*--*/
        display: inline;
    }
    div#menu_vert {
        float: left;
        width: 8em;    /* Width of the menu -- */
        height: 100%;
        position: fixed; /* Do not scroll with the page --*/
        display: inline;
        margin-left: -1.5em;
        top: 0;
    }
  div#menu_vert img {  /* A picture attached to the menu --*/
        width: 8em;
        margin-bottom: 1em;
    }
This works beautifully with firefox, opera and konqueror. It validates through the wwwc-checker too. Yet, for some reason IE6 puts the menu below the content. So on pages with lots of content the menu bar will end up way below the visible part of the window. (e.g. http://lilalaser.de/lila/index.php/deutsch/produkte/diodenlaser). Is there a workaround to get the desired behaviour with IE?
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