[SlimDX DX9] Strange UV Offset while rendering FS Quad

Hello,

at first I'm new with SlimDX and DirectX, before I was working with OpenGL. So to my question.. I'm rendering a scene to seperate RenderTarget and try to render the resulting texture with a fullscreen quad. This works nice, but I'm having a strange one-pixel UV offset. So what I have done to see this:

1. I'm rendering a test texture with FullScreenQuad to a RenderTarget which haves the same size as Backbuffer

2. I save the result of Rendertarget to a texture using StretchRectangle

3. I render this texture with a FullScreenQuad in the Backbuffer

Now i can see that I'm having one pixel offset on left and upper side. If I render the test-texture directly to the BackBuffer, using the same code for FullScreenQuad, I don't have this offset.

So what I'm doing wrong?

Thanks for help,

Thomas