jqGrid - saving checkbox selected state without using multiselect

I am using jqgrid and created a grid and using formatter for the last column as checkbox (not on the multiselect).Checking checkboxes across pages in jqGrid wipes out the selected checkboxes. So, if I check some checkboxes on page 1 and then click Next to go to page 2 and then come back to page 1, the selected checkboxes are no longer checked.

Thank u