Hi David, all, Just an update: I've been looking for a solution for validating documents using the schemas but without having the core referring to the modules. I'm trying to work with NVDL which seems to be designed to do exactly that: validating compound documents. It looks like the FS module should be OK: We just have to specify a mode where the attributes of the element in context are checked for the FS namespace, and use that mode on any element where FS is allowed. I have a test on unit that works. For the modules using elements: so far I can get the elements of a module (Metadata) to be validated, but not to validate where the elements of that module are allowed. Currently, for example, moving the metadata element before the <segment> is still seen as valid. I've attached my NVDL script in case someone has some knowledge of NVDL and can make suggestions. Cheers, -yves Attachment: test.nvdl Description: Binary data