Page with explicit size, margins and orientation

I need to produce a page with a specific size (width and height), distinct margin values for the four margins. My code looks like this:

_t.Width = 11.0
_t.Height = 8.5f;

_t.Left = _t.Right = 0.3f;
_t.Top = _t.Bottom = 0.5f;

            // Set up the page dimensions based on the values from the T2PForm file
            DP.Dimensions pagedim = new DP.Dimensions(_t.Width, _t.Height);
            DP.Dimensions margindim = new DP.Dimensions(_t.Left,_t.Top,_t.Right,_t.Bottom);
            _dimensions = new DP.PageDimensions(pagedim, margindim);

However, when I print, the page comes out in portrant orientation, truncating content that extends beyond the portrait page.

I can't find a way to set both the custom margings and the page orientation.

Oops... all the dimensions in the OP should be multiplied by 72 (points per inch)

Oops... all the dimensions in the OP should be multiplied by 72 (points per inch)