Since this request has drawn no replies, maybe post it with a different question, spelling out more what you need. However, not knowing your program, I will comment. About the best that I can imagine is this: First print out the file sketch. Draw on it what you mean to add. Then, ether scan or take a photo of it and use that as if it was the original file.

Under SKETCH go to PICTURE, click INSERT, select the *.bmp image file and choose some installation base point that doesn't matter for now. Next click SCALE (with your *.bmp file selected under SKETCH, PICTURE). This will allow you to choose 2 scale points (A & B). After you click the 2 scale points, a "SCALE PICTURE" window pops up allowing you to change the coordinates for A & B. Click APPLY (under the SCALE PICTURE window) to scale the image file or DEFINE if you wish to re-pick points A & B. Easy!