Problem with LiquidCrystal library

Hi,

I am having troubles with the liquidcrystal library on my arduino due...
At first my lcd did very weird. Showed some unknown characters etc... After troubleshooting a couple of hours I discovered the problem. The RS pin was constantly high. At the beginning of the program when the program initialises the lcd the pin comes low. But after that it stays high for every other command. It comes high before entry set mode. So here it already fails.
Now when I make the RS pin manually an output in my main program the library works just fine, BUT the text on the lcd is very light. You almost can't see it... This has nothing to do with the contrast pin, this because when I didn't make the RS pin manually an output the contrast was perfect. Only the display did no what I wanted. Now it does what I wan't but the contrast is super low.
What is wrong here?

Sorry for my bad English...