求助淘宝主动通知SIGN签名 (delphi)

[lian_yu]

App Key：12026694
App Secret：82c76d2c7049e5252ae4b05da482c3b7

sign_methods:='md5';
timestamps:= FormatdateTime('yyyy-mm-dd hh:nn:ss',now());
vs := '2.0';
methods:= 'taobao.increment.trades.get';
partner_ids:='top-apitools';
app_keys:='12026694';
sessions:= '6101e24b4e98307e19deeee54ac434b111511e592f0425d17975612';
formats:= 'xml';
nicks:='liyu873';
Secret_key:='82c76d2c7049e5252ae4b05da482c3b7';
si:='app_key'+app_keys+'format'+formats+'method'+methods+'nick'+nicks+'partner_id'+partner_ids+ 'session'+sessions+'sign_method'+sign_methods+
'timestamp'+timestamps+'v'+vs;


si:=(StrMD5(Secret_key+si+Secret_key));
Params:=TStringList.Create;
Params.Values['app_key']:=AnsitoUtf8(app_keys);
Params.Values['format']:=AnsitoUtf8(formats);
Params.Values['method']:=AnsitoUtf8(methods);
Params.Values['nick']:=AnsitoUtf8(nicks);
Params.Values['partner_id']:=AnsitoUtf8(partner_ids);
Params.Values['session']:=AnsitoUtf8(sessions);
Params.Values['sign']:=AnsitoUtf8(si);
Params.Values['sign_method']:=AnsitoUtf8(sign_methods);
Params.Values['timestamp']:=AnsitoUtf8(timestamps);
Params.Values['v']:=AnsitoUtf8(vs);

strxml:=IdHTTP1.post('http://gw.api.taobao.com/router/rest?',Params);

麻烦各位帮我看一下,是哪里出错了，为什么总提示签名（sign）无效
上面的App Key，App Secret的值是无效的，只用来举例用的。

[lian_yu]

没有高手回答，自己顶一下吧。

[lian_yu]

等待解答中.....

[lian_yu]

sign是不是这样拼接(StrMD5(82c76d2c7049e5252ae4b05da482c3b7app_key12026694formatxmlmethodtaobao.increment.trades.getnickliyu1973partner_idtop-apitoolssession6101e24b4e98307e19deeee54ac434b111511e592f0425d17975612 sign_methodmd5timestamp2013-06-06 12:30:15v2.082c76d2c7049e5252ae4b05da482c3b7))