Small-to-medium enterprises (SME) are frequent. It holds for SME software users as well as for SME software developers. Both cannot exclusively use products and philosophies of large software vendors. SME users have not enough resources to apply or implement products and processes of large vendors. The processes can be based on philosophy not applicable in SME. It follows that SME must collaborate with SME software vendors and use their solutions. It can happen that even great users must use solutions of small software vendors solving special needs. We show that these challenges can be solved if we apply a variant of service-oriented architecture using document-oriented communication. The communication is supported by infrastructure services. Our experience shows (see examples) that it can have dramatic effects.