Tomcat – PHP and JSP running on same machine.. Tomcat on Apache

Have you tried something like this (assuming you've loaded mod_rewrite)?

RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^/low(.*) https://%{SERVER_NAME}/low$1 [R,L]

If you use Apache Httpd as a frontend, that's where SSL needs to be configured (see documentation for the mod_ssl module).

Typically, this will look like this:

<IfModule mod_ssl.c>
<VirtualHost *:443>
        ServerAdmin webmaster@host.name.example
        ServerName host.name.example

        SSLEngine       on
        SSLCertificateFile      /etc/ssl/certs/host.pem
        SSLCertificateKeyFile   /etc/ssl/private/host.key

        # ...
        # (the config file with your distribution will probably have
        #  a sensible set of options for SSL as well.)

        JkMount  /high/* loadbalancer
        JkMount  /low/* webworker
</VirtualHost>
</IfModule>

<VirtualHost *:80>
        ServerAdmin webmaster@host.name.example
        ServerName host.name.example


        # You can put the rewrite rules here for example.

        JkMount  /high/* loadbalancer
        # Don't put this one if you don't want it over plain HTTP
        # JkMount  /low/* webworker
</VirtualHost>

Read more about mod_proxy_ajp or mod_jk. One of these modules will help you to have tomcat apps served by apache.
You cannot have two services on the same port, unless, you bind the services to different IPs.
Assuming you have two IPs you bind apache on first IP port 80 and tomcat on the second.

The easiest is using apache modules. Search for tomcat and apache configs that meet your needs.

HTH