In order to generate an expansion, it's not sufficient to list the codes in the value set. The code system in which the codes are defined must be available. (Theory is that some of the codes may have been deprecated, etc., so even though they're listed in the value set, they aren't part of the expansion.) To make the expansion work, you'll need to actually create CodeSystems (whole or partial) for the ones that don't yet exist in FHIR.