- Get acquainted with and install Eclipse.
 - Install and learn oAW Xtext.
 - Define a grammar and generate the code.
 - Deploy the editor at the customer's side.
 
All of that within 5 days. What does that mean
- That guy is really a wizard.
 - Eclipse is very easy to install and use.
 - Xtext can really give you a head-start into modeling.
 
It feels so good to have such a mighty toolstack at hand :-)