There are several methods, using the PDF process and object tool being one. You can also add a button (under TOOLS>FORMS depending on AA version) and use the graphic as the button display. The advantage of the button is that you can control placement and size. You can not control the size of the object copy route.
The other answer is more obvious. Add the graphic to the original document and create a new PDF. That is ALWAYS preferred.
I am also having trouble inserting an image/graphic into a PDF document.
My problem is that the "paste" "Ctrl-V" is alway greyed out.
I can copy the image (From an pdf document) using the Snapshot tool. but then I cannot find how to paste that image from the clipboard!
Convert the graphic to a PDF document. - okay done.
Activate the TouchUp Object Tool. - where is this? I can find the select object tool and the Touch up Text tool, both do not select or copy the image.
Select and copy the graphic. - Okay I can do this with the snapshot tool.
Open your document. - easy done.
Paste the grphic. - HOW?????
This is using Acrobat 9.1
You can not copy a graphic from the clipboard. You have to copy it from another PDF (not the Windows clipboard) or insert on a button. That was explained earlier. Give them a try. Keep in mind, a PDF is not an object that was meant to be edited and in general you should being such things in a typical creation tool (not Acrobat) and then creating a new PDF.