Convert str to Date while importing from XML into AIF

When we are importing the date from xml to AIF we cannot convert that string to date using str2date().
The following function is used to convert from str to date.

Date ConvertXMLStrToDate(str _xmlValue)
{
    System.DateTime                 netDttm;
    str strTransDateTime;
    utcdatetime                     TransDateTime;
    ;
    new  InteropPermission(InteropKind::CLRInterop).assert();
    netDttm = System.DateTime::Parse(_xmlValue);
    TransDateTime=Global::utcDateTime2SystemDateTime(netDttm);
    return dateTimeUtil::date(TransDateTime);
}

Call from job

static void krishh_ConvertXmlStrToDate(Args _args)
{
date datevar;
System.DateTime                 netDttm;
str strTransDateTime;
utcdatetime                     TransDateTime;
EDSA_CreateSalesOrder createsales;
;
createsales=new EDSA_CreateSalesOrder();
strTransDateTime='2011-08-25 00:00:00';
datevar=createsales.ConvertXMLStrToDate(strTransDateTime);
}