KNX Send value to blind

[PITP2]

Hi,
i 'm trying to open and close a blind.
I can open and close the blind sending 0 or 1 to the correct adress group

But i can't send a position to the blind. I use the good adress group.
When i look the informations on the knx bus whe i  use an other software that works i have this

LPDU: B8 FF FA 19 04 E2 00 80 CC F1 :L_Data normal from 15.15.250 to 3/1/4 hops: 06 T_DATA_XXX_REQ A_GroupValue_Write CC

But when i use FHEM i have that :

LPDU: BC 00 00 19 04 F1 00 BF 10 :L_Data low from 0.0.0 to 3/1/4 hops: 07 T_DATA_XXX_REQ A_GroupValue_Write (small) 3F

Is someone can help me ?

[PITP2]

i think that the problem become of the format value

There is "(small)" when Fhem sends data to the knx bus