I found this from other online forums....
Capture the binary value using web_reg_save_param and then convert the value using
web_reg_save_param("ParamCaptureBinaryValue",
"LB/IC=name=\"__EVENTVALIDATION\" id=\"__EVENTVALIDATION\" value=\"",
"RB/IC=\" />",
"Ord=1",
"Search=Body",
"RelFrameId=1.2",
LAST);
web_convert_param("Param12",
"SourceString={ParamCaptureBinaryValue}",
"SourceEncoding=HTML",
"TargetEncoding=URL",
LAST);
Pass Param12 in Binary body "BodyBinary=V\\x02\\x0B\\x01s\\x04\\x0B..........)
"BodyBinary={Param12}
Try this..
Good luck
