Automate Daily Sage 50 Invoice Posting

I already have sales invoices sitting in our Sage-native database and need them posted automatically into Sage 50 Accounts (UK). Using the Sage 50 COM/SDK, please create a small Windows service or script... (Budget: £1000 - £1100 GBP, Jobs: .NET, API Development, Automation, C# Programming, Database Management, PHP, Software Architecture, Windows Service)