How to include another rhtml from an rhtml (no controller)...

I'm trying to do something simple like...

In _email_header.rhtml

<% include "header.rhtml" %>

Where _header.rhtml looks like ...

<div class="bdy90">
  <%= image_tag "logo.gif", :class => "logostyle" %>

  <ul id="topnav">
    <li>
      <a class="request" href="https://www.xyz.com">
        <strong>Request Service</strong>
      </a>
    </li>
    <li>
      <a class="contact" href="https://www.xyz1.com">Contact Us</a>
    </li>
  </ul>
</div>

The wrinkle is that main.rhtml is a template.

I'm trying to clone the look of my pages in my email...

Thanks,
Jason

render :partial => "main.rhtml"

This is from rails docs.

Rendering a template

Template rendering works just like action rendering except that it
takes a path relative to the template root. The current layout is
automatically applied.

  # Renders the template located in
[TEMPLATE_ROOT]/weblog/show.r(html|xml) (in Rails,
app/views/weblog/show.rhtml)
  render :template => "weblog/show"

Rendering a file

File rendering works just like action rendering except that it takes a
filesystem path. By default, the path is assumed to be absolute, and
the current layout is not applied.

  # Renders the template located at the absolute filesystem path
  render :file => "/path/to/some/template.rhtml"
  render :file => "c:/path/to/some/template.rhtml"

  # Renders a template within the current layout, and with a 404 status code
  render :file => "/path/to/some/template.rhtml", :layout => true,
:status => 404
  render :file => "c:/path/to/some/template.rhtml", :layout => true,
:status => 404

  # Renders a template relative to the template root and chooses the
proper file extension
  render :file => "some/template", :use_full_path => true