关于C#调用C++ DLL的问题

int __stdcall RecvSms(

				char *sOrgAddr,			//返回：源址

				char *sPhone,			//返回：手机号

				unsigned char *sMsgID,	//返回：上行或状态报告的msgid

				unsigned char *ReportFlag, 	//返回：信息标志 0:状态报告 1:上行

				char *sTimeStamp,		//返回：接收到的时间 格式：2009-10-28 12:12:12	

				char *sSubmitdate,		//返回：提交时间0910281212

				char *sDonedate,			//返回：受理时间0910281212

				char *sErrorCode,		//返回：状报告错误码

				char *sMsg				//返回：上行信息

				);

char sOrgAddr[22] = {0};

char sPhone[22] = {0};

unsigned char sMsgID[25] = {0};

unsigned char ReportFlag[2] = {0};

char sTimeStamp[20] = {0};

char sSubmitdate[20] ={0};

char sDonedate[11] = {0};

char sErrorCode[8] ={0};

char sMsg[1024] = {0};

iRet = RecvSms( sOrgAddr,			//源址

		sPhone,				//手机号

		 sMsgID,				//上行或状态报告的msgid

		 ReportFlag,    		//信息标志 0:状态报告 1:上行

		 sTimeStamp,			//接收到的时间，	

		 sSubmitdate,			//提交时间200910281212

		 sDonedate,			//受理时间200910281212

		 sErrorCode,			//状报告错误码

		 sMsg				//上行信息

	         );

 [DllImport("SMEIDll.dll", EntryPoint = "RecvSms")]

    public static extern int RecvSms(StringBuilder sOrgAddr, StringBuilder sPhone

                    , ref int sMsgID, ref int ReportFlag, StringBuilder sTimeStamp

                    , StringBuilder sSubmitdate, StringBuilder sDonedate

                    , StringBuilder sErrorCode, StringBuilder sMsg);