When I try the following code, a part of the line gets overwritten. Is there a way to print the text transparent over the line?

GUI_RECT textbox;


textbox.x1=100;
textbox.x0=0;
textbox.y1=100;
textbox.y0=0;
GUI_MoveTo(0,0);
GUI_DrawLineTo(500,500);
GUI_MoveTo(0,0);
GUI_MEMDEV_Handle hMenAlignment = GUI_MEMDEV_CreateFixed(0, 0,
100,
100,
GUI_MEMDEV_HASTRANS,
GUI_MEMDEV_APILIST_32, GUI_COLOR_CONV_888);

GUI_MEMDEV_Select(hMenAlignment);
GUI_SetBkColor(GUI_TRANSPARENT);

GUI_DispStringInRectEx("test",&textbox,0,4,0);
GUI_MEMDEV_Select(0);
GUI_MEMDEV_WriteAt(hMenAlignment,0,0);
GUI_MEMDEV_Select(hMenAlignment);

i'm trying the speedometer sample. The _RollIn and _RollOut functions don't work.