For your developers, we turnover the
             CV2VB tools used to build your application.

We don't convert CorVision-generated source code - we generate it too, with some powerful CorVision-like tools. 

Unlike CorVision, you are not forced to use these tools.  And all the source code is in a non-proprietary language.

Considering that 85% of the source code is generated, you might want to consider using the CV2VB toolset:

 

CorVision repository or CV2VB repository	Holds the application model and business rules.
CV2VB Code Generators	VB.NET or ASP code generators
CV2VB Menu Editor	Defines the menus the users see, their security, and transactions across multiple forms.
CV2VB HELP Builder	Extracts business rules from the model and combines them with your annotations to produce online HELP.
CV2VB Batch Manager	Queues report and batch procedures, gives job status, archives and distributes reports.
CV2VB Data View Editor for end use QUERY	Designs the data views which end users can select in  CV2VB's QUERY.
any HTML editor (for ASP)	Change layout of screen forms and the application's cascading style sheets.
Active Reports (VB)	Define report layout, totals, breaks, headings.