do i have to make a template or what?
If you only want this subdomain (and not
www.phpmyadmin.*, mail.phpmyadmin.* etc.), you can do this with templates as well.
Create a directory with the name of the full domain name, in your case: phpmyadmin.jurgen-meijer.nl in the /etc/e-smith/templates-custom/etc/httpd/conf/httpd.conf/ folder and create template folders for the subdomain there. You will have to know about configuring apache if you would like to do this.
I made it myself a little bit easier by copying in a few sections of the VirtualHosts folder and modifying the necessary sections to my linking. The list for one of my subdomains for instance consists of the following templates:
-rw-r--r-- 1 root root 322 Sep 18 2003 00Setup
-rw-r--r-- 1 root root 30 Mar 14 2006 02ServerName
-rw-r--r-- 1 root root 196 Jan 24 2003 25SSLDirectives
-rw-r--r-- 1 root root 125 Mar 14 2006 26RewriteTraceAndTrack
-rw-r--r-- 1 root root 192 Jan 7 2003 50DirectoryIndex00
-rw-r--r-- 1 root root 255 Mar 17 2006 50DirectoryIndex00PHP
-rw-r--r-- 1 root root 82 May 13 2003 50DirectoryIndex01
-rw-r--r-- 1 root root 215 Jan 7 2003 85DefaultAccess
-rw-r--r-- 1 root root 61 Jan 20 2007 99yum.snetram.nl
-rw-r--r-- 1 root root 36 Jan 7 2003 template-begin
-rw-r--r-- 1 root root 16 Jan 7 2003 template-end
I modified the 02ServerName to only display the subdomain name I specified, so all other configured hostnames are left out. The last fragment 99yum.snetram.nl holds the configuration that exposes my yum directories to the internet.