使用ASP.NET兼容模式的WFC Rest服务 - 如何设置大型POST请求？

Good Morning community, I hope you can help me with an issue I'm facing right now. I have a WFC REST Service using ASP.NET Compatibility mode (so i can ignore the .svc endpoint in the url). My REST Service is receiving XML and returning XML as well. when testing with different POST Request I get an error 400 for the POST. my XML test files between 100 Kb and 200 Kb.Good Morning community, I hope you can help me