Hello Paul,

As part of internal D3 discussion we took another close look at this issue and think the support can be done in two steps:

1) We will enhance our current XSD logic to address large schema objects such as UBL better. This will be done as part of 5.2 GA and hopefully a beta version will be ready for you to try out soon.

2) We can consider exposing an extension point in our Designer to allow customers to hook in custom logic for instantiating/initializing large schema objects such as UBL. This can be addressed as a D3 project.

Thanks very much for your feedback!

Shao.