Choice of CASE tool for a Navision Financials customization

Hi,

I am in search of an appropriate CASE tool, which can be used in a NF customization project. I have following queries in this regard:

1. Does anybody know which CASE tool(s) is being used by Navision for its products ?

2. Where can one find an Object Model of NF ?

3. How can one import NF process model, ERD, Object model in Sybase PowerDesigner 6.0/7.0/8.0 ?

4. How can one get to see NF business rules/application logic from a designer's view point?

Thanks in advance,

Alok