Belgian Immigration Advice for UK Contractor

I need expert advice on the best visa or work permit route for a UK company director/contractor. I will be providing long-term warehouse and logistics services in Belgium and want to invoice our Belgian company, not be employed... (Budget: €30 - €250 EUR, Jobs: Business Consulting, Contract Management, Contracts, Immigration, Immigration Law, Legal, Legal Consultation, Legal Research, Legal Writing, Visa / Immigration)