I’m not really clear from your description what you’re trying to do, but you should not define “xmlns” or “xmlns:xsi” as attributes in your schema. Although they look like attributes, they are not: they’re namespace declarations. In your schema you need to have appropriate namespace declarations, and the elements and attributes should be defined in the appropriate namespaces, and then it should work.
Also, each Schema document should only define elements in a single namespace. If (as it appears here) you have elements from different namespaces in a single instance document, you’ll need to create a Schema document for each namespace and use the import function to combine them.
If you want to wrap your document by a namespace-free element SupplierSchedulerConfig, you have to define a second schema that imports the schema above.
Hint: importing schemas are very much more conveniant in Tamino V4.4, so you should switch versions.