从 SQL Server 调用 Web 服务

I try to call my web method from T-SQL code but it neither works nor yields any exception or error.

代码如下:

sp_configure 'show advanced options', 1;
GO

RECONFIGURE;
GO

sp_configure 'Ole Automation Procedures', 1;
GO

RECONFIGURE;
GO

Declare @Object as Int;
Declare @ResponseText as Varchar(8000);

Exec sp_OACreate 'MSXML2.ServerXMLHTTP', @Object OUT;

Exec sp_OAMethod @Object, 'open', NULL, 'get',
    'http://vserver250:8600/EcomSmsSvc.asmx/Reply?message=hi','false'

Exec sp_OAMethod @Object, 'send'

Exec sp_OAMethod @Object, 'responseText', @ResponseText OUTPUT

Select @ResponseText

Exec sp_OADestroy @Object

我的网络服务工作正常，当我通过网络浏览器调用它时，它返回我发送的消息，但是当我从 T-SQL 调用它时，结果总是 NULL.