NWDS 711: backward compatibility?

Hi developers,

I am customising the Billing Direct application by Sap using the publicly available SCAs.

I would like to use NWDS 711 but the web applications are 1.4 based.

What I have done so far:

- installed JDK 1.4 on my laptop

- configured project specific settings on the required projects

I still keep getting version related errors such as: "enum is a reserved keywork in java 5"

How do I specify to build a certain DC with Java 1.4 compiler?

Thanks, regards

Vincenzo