VBA code for setting Income value

Hi experts

I'm writing macro for Asta and hit the wall when I want to assign income value in task.

Below code finds Income Cost Centre assigned, but can't find a way to set value.

Dim t As TaskBase

Dim bcv As BarChartView
Dim ca As CostAllocation

 Set bcv = ap.CurrentView
 AllTasks = bcv.AllTaskBaseIds
  For Each act In AllTasks    
     For i = 1 To t.Allocations.Count
             Set ca = t.Allocations(i)
         'here I need to set income value on this task 
      Next i
 Next act


Thank you in advance for any hints!