Thomas, not a problem. While very powerful the templating system can often be confusing and "cumbersome" for new users. What you want to do is:
# Create a custom template directory
console>mkdir -p /etc/e-smith/templates-custom/etc/ppp/ip-up.local
# Create the actual template
pico -w runonconnect
# Add the code to run the file/binary you wanted. Save your changes.
# Expand the template
/sbin/e-smith/expand-template /etc/ppp/ip-up.local
Next, pico /etc/ppp/ip-up.local making sure your changes are visible and in the correct position. I'm not very familiar with ppp because I use broadband. If it's expanding the custom template in the wrong place you can always edit the template directly. This isn't advisible but sometimes it's a solution.
The master templates are stored in /etc/e-smith/templates
Hope this helped. The templating system is very powerful, easy to use, and an excellent solution to controlling configuration files.
Nathan