I'm not sure how you do that. Is that in Firebug?
I did use the the builder Test button on the service. And It runs just fine. See JSON data below.
("FrKode" in norwegian (see picture above) means Absence code or AbsCode as you can see in the JSON data underneath. Dag=Day, Data=SummaryColDay)
{
"result":[
{
"SummaryColTotal":"49.57",
"TimeSheetLocked":"0",
"Data":[
{
"Day":"1",
"ClockingsSummary":"02.00-18.00",
"SummaryColDay":"6.00"
},
{
"Day":"2",
"ClockingsSummary":"08.40-16.00",
"SummaryColDay":"-0.40"
},
{
"Day":"3",
"ClockingsSummary":"18.12-20.16",
"SummaryColDay":"2.04"
},
{
"Day":"4"
},
{
"Day":"5",
"AbsCode":"FML"
},
..
...
..