writing in specific cells

[MS]

Hi,

I am developing an application where I read some columns and then write the 
output in another column. The problem is that whenever I write the output, 
it is being written in the cells after all columns end not from the 
beginning of the column. So I end up with something like this: 


<https://lh6.googleusercontent.com/-lavK_I400AE/T9xqjMc9ULI/AAAAAAAAAAU/qke8G8xOgtY/s1600/test.jpg>

Any ideas on how to begin writing from the beginning of the column? 

I am using the java API and here is the code I use to write a new cell:

ListEntry newEntry = new ListEntry();
newEntry.getCustomElements().setValueLocal(where, op);
ListEntry insertedRow = myService.insert(listFeedurl, newEntry);


where is the column header name, which in this case is start and op is the 
output.

Thanks