I have troubles with fillPoly function in DirectGraphics interface.

I'm testing my application on 7650 MIDP Emulator, it works fine.

Having done the first good version of application I tried it on the actual Nokia 7650 device.
And it seems like DirectGraphics.fillPoly(...) function is not iplemented on the actual device.
It works without any exceptions, but does not draw polygons at all

Could you help me with this trouble ? Why does it not draw polygons ?

I've tried different values for alpha component for colors.
If alpha equals F(4 bits for 7650), then it is visible neither on the emulator nor the actual device.
If alpha equals 0(4 bits for 7650), then it is visible on the emulator, but invisible on the actual phone.

Do you have any other ideas how to solve this problem ?