好像我找到了解决方案.我刚刚添加了第二种方法:

Looks like I have found solution. I just added second method:

[<OperationContract>]    
[<WebInvoke(UriTemplate = "PostTest", 
        RequestFormat= WebMessageFormat.Json,   
        ResponseFormat = WebMessageFormat.Json, Method = "POST")>]         
abstract PostTest: obj: Test -> unit

[<OperationContract>]    
[<WebInvoke(UriTemplate = "PostTest", 
        RequestFormat= WebMessageFormat.Json,   
        ResponseFormat = WebMessageFormat.Json, Method = "OPTIONS")>]         
abstract PostTestOptions: unit -> unit

只是空方法，什么也不做.我不知道原因，但是一切正常.

It is just empty methods that do nothing. I don't know the reason, but all is working.