DataWindow.Print.Paper.Source not working

hi to all,

i'm trying to change the paper source for a printer before printing a datastore, but it seems to not work.

i have tested all the paper.source values in this way with no success.

for ll_c = 0 to 14

    lds_1.modify ("DataWindow.Print.Paper.Source='" +string(ll_c)+"'")

    if ll_s <> '' then messagebox(ll_s ,ll_c)

    lds_1.print()

next

the problem is present either in  pb 12.6 and pb 11.5 also using different printer models

what's wrong?

Thanks in advance