Lighttpd

(my first website is on 192.168.1.99:80)

in the html of my first website - <mySite.html> - I have:

<p>
<a href="http://192.168.1.99:8080&quot;&gt;go to the other server</a>
</p>

when I am surfing within my local network, pushing the text 'go to the other server' works fine, I get redirected to the site 192.168.1.99:8080
when I am accessing this page from external, that does not work as 192.168.1.99:8080 is an internal local address in my network and it has no sense trying to access that from outside my network

How to solve? I have the 2 sites running on the same Lighttpd webserver (one site is CGI & one is HTML, but I do not think this specifically matters)
I think I need to get such done with url.rewrite and/or proxy stuff but I do not get it configured.

Can anyone help me out and tell what to write in the href, and what to add in the lighttpd.conf file?
Thanks a lot