When you place the PDF file, either check Show Import Options (or hold down the Shift key) to display the Place PDF dialog box.
Click on the General tab, and you can choose how you would like the artwork to be cropped. I believe you probably want the Trim option.
after you place the file, reduce the image box to the size of the crop area.
Thanks! It only lets me have 1 'correct' answer, but obviously this is correct too - and a big help.
YOu should specify for those PDFs DF/X-4 standard with bleed, no need to add cropp marks.
Never ask for PDF/X-1a or X-3 or print ready, as only X-4 with RGB images allows best quality for you, even if you need later PDF/X-1a, X-3 or interactive PDFs.