hi nitin,
i do not know how HP-UX 10.2 works since i use version 11.. but still i would share what i know with you.
for changing the icon or make it a funny thing you will have to edit some files.
if your system has the .dt folder try to explore that and try to change the animations part in the
dtwm.fp file.
if u can do this.. i hope i would help u more.
all the best.