Try this code....
-(NSDictionary*) getTimeCardActivityDetailService:(NSString *)userName:(NSString *)passWord
{
NSString *dataBase = [self getDatabaseNameFromPlist];
strxml = @"<soapenv:Envelope xmlns:soapenv=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:xyt=\"urn:xytechsystems.com/XytechAPILite\" xmlns:xyt1=\"http://schemas.datacontract.org/2004/07/Xytech.MP.API\" xmlns:arr=\"http://schemas.microsoft.com/2003/10/Serialization/Arrays\" xmlns:i=\"http://www.w3.org/2001/XMLSchema-instance\">";
strxml = [strxml stringByAppendingString:@"<soapenv:Header/>"];
strxml = [strxml stringByAppendingString:@"<soapenv:Body>"];
strxml = [strxml stringByAppendingString:@"<xyt:GetItemsiOS>"];
strxml = [strxml stringByAppendingString:@"<xyt:credentials>"];
strxml = [strxml stringByAppendingString:@"<xyt1:DBName>"];
strxml = [strxml stringByAppendingString:dataBase];
strxml = [strxml stringByAppendingString:@"</xyt1:DBName>"];
strxml = [strxml stringByAppendingString:@"<xyt1:Password>" ];
strxml = [strxml stringByAppendingString:passWord ];
strxml = [strxml stringByAppendingString:@"</xyt1:Password>" ];
strxml = [strxml stringByAppendingString:@"<xyt1:UserID>" ];
strxml = [strxml stringByAppendingString:userName ];
strxml = [strxml stringByAppendingString:@"</xyt1:UserID>" ];
strxml = [strxml stringByAppendingString:@"</xyt:credentials>"];
strxml = [strxml stringByAppendingString:@"<xyt:className>TimeCardActivities"];
strxml = [strxml stringByAppendingString:@"</xyt:className>"];
strxml = [strxml stringByAppendingString:@"<xyt:includeMetaData>"];
strxml = [strxml stringByAppendingString:@"FirstRowOnly"];
strxml = [strxml stringByAppendingString:@"</xyt:includeMetaData>"];
strxml = [strxml stringByAppendingString:@"<xyt:criteria>"];
strxml = [strxml stringByAppendingString:@"<xyt1:Criteria i:nil=\"true\"/>"];
strxml = [strxml stringByAppendingString:@"<xyt1:MaxRows>0</xyt1:MaxRows>"];
strxml = [strxml stringByAppendingString:@"</xyt:criteria>"];
strxml = [strxml stringByAppendingString:@"</xyt:GetItemsiOS>" ];
strxml = [strxml stringByAppendingString:@"</soapenv:Body>" ];
strxml = [strxml stringByAppendingString:@"</soapenv:Envelope>" ];
NSString * xmlResponse = [self callWSForGettingActivityDetail:strxml];
NSDictionary *activityDetailDic= [self loadDataFromXMLOfActivityDetail:xmlResponse];
using nsstring variable by appending such tag with db name/password (credentials)