how to set the datetime parameter default value = 11:59:59 pm

my report has a report parameter with datetime datatype, I want to set its default time to 11:59:59 pm without specifiy the date, is this possible?
Also, when I import the report to Tivoli Common Reporting, I found the datetime parameter field is split to two component, one for date input and another for time input, will this affect the default tiime setting?
My birt designer version is 2.2.1