HTML in addon

[[xFv]]

Hello all!

I am creating an addon that requires html to be parsed from the addon admin style property textbox.
For example if I were creating a Notices addon and need to use something like this "{$user.user_id}" inside the Textbox to be parsed,
how would I achieve that?
I just get unparsed HTML.

I am using a Named Template with this code:

<input type="hidden" name="checkboxes[]" value="{$property.property_definition_id}" />

<xen:textboxunit name="properties[{$property.property_definition_id}]" value="{$property.propertyValueScalar}" label="{$property.title}" rows="5">
    <xen:hint>{xen:if $debugMode, $property.property_name}</xen:hint>
    <xen:explain>{$property.description}</xen:explain>
    <xen:html><xen:include template="style_property_unit_extra"><xen:set var="$reset">{xen:phrase reset}</xen:set></xen:include></xen:html>
</xen:textboxunit>

And here is my template code:

<xen:if is="@xfv_message_switch" />
   <div class="xfv_message_box">
      <div class="xfv_message_close">
            <button type='button' class='close' onclick='$(this).parent().remove();'>X</button>
         <div class="message_username">
            <i class="fa fa-exclamation fa-lg"></i> Welcome {$visitor.username}...
         </div>
            @xfv_message_member
      </div>
   </div>
</xen:if>

This is the call to my Textbox option: @xfv_message_member

ThanX!