How to resolve error messages from tax agency related to Spain SII report?

I have three problems related with the issue of the SII file correctly.

-For received invoices: the spanish vendors have NIF and the information goes right in the SII file, but the international vendors are treated as spanish vendors so the tax agency issue an error message saying that the NIF is wrong. I need the tax information for the international vendors treated as a "document" and not as a NIF like they were from Spain.

-For issued invoices: if a customer has an OSS tax code in the invoice then the SII file doesn't contain the invoice.

-For issued invoices: all the customers are treated as if they were from Spain, because every invoice in the file has the S1 code. For example, the invoices that has the intra community tax code for customer outside of Spain but in the european community, the SII file treat the customer as if it is in Spain and then the SII code S1 is assigned.