Displaying Data from UD Table in UltraGrid and Saving it back

I have an UltraGrid on my customized screen. I am able to displaying data from UD07 Table on that Grid, but I can't save it back. After UD07.GetRows method UD07Adapter.UD07DataSet remains empty. Why?

My code

/* Variable Definition */
Dim adaUD07Adapter As UD07Adapter
Dim dsUD07Adapter As UD07DataSet

/*- then I am connecting to BO,
setting all necessary SearchOptions -*/

/* Pulling data from DB */
dsUD07Adapter = adaUD07Adapter.GetRows(optsUD07, MorePagesUD07)

/*and then when checking for data in 'dsUD07Adapter'*/
MessageBox.Show("dsUD07Adapter: " & dsUD07Adapter.Tables("UD07").Rows.Count.ToString)
/*it shows me that I have 13 rows in table*/

/*but UD07DataSet is empty*/
MessageBox.Show(adaUD07Adapter.UD07Data.Tables("UD07").Rows.Count.ToString
/* Above code shows that I have 0 rows */

I am able to modify data in dsUD07Adapter but I can't save it back using adaUD07Adapter.Update because adaUD07Adapter.UD07DataSet is empty.