>Thank you both, Charlie & James. Let's suppouse that I'm subclassing the D.E. in a programmatic
>way. How do I force the new forms created by CREATE FORM [...] to use the new D.E. class ?

In the load event of the form you could put the following code

This.addobject("oDataenvironment", "myDataEnvironment")

This would add the dataenvironment object to the form
object and you could access using oForm.oDataEnvironment. That's just one of many different way to achieve what you are trying to do.