The easiest way to convert a Julian date into day, month, year, hour and minutes format is to use of the AcDbDate class. Also, visit this post for more information.
struct resbuf rDate;
double time, fpart, ipart;
acedGetVar(_T("DATE"), &rDate);
time = rDate.resval.rreal;
fpart = modf (time, &ipart);
AcDbDate testDate;
testDate.setJulianFraction(fpart);
acutPrintf(_T("\nMinute: %d\nSec: %d\nMilisec: %d"),
testDate.minute (),
testDate.second (),
testDate.millisecond ());