Here's the only way I could get this to work in Word 2000:
Right click on the clip art image.
Click Format Picture.
Click the Layout tab and choose Square (or Tight)...just
avoid the In line with text choice, and click OK.
Right click on the image again.
Click Grouping, then Ungroup.
Immediately, and while it's still ungrouped, right click
on the image again, click Grouping, then Group.
Copy and paste the image. For ease of seeing what you're
doing, you will probably need to move the pasted image to
the right of the original.
You should then be able to use the Rotate or Flip command
on the copied image from the Drawing toolbar: Click
Draw|Rotate or Flip|Flip Horizontal. (If the Drawing
toolbar isn't showing, go to View|Toolbars and make sure
there's a checkmark next to Drawing).
If you want the 2 images to stay together, be sure to
select both of them, right click and choose
Grouping|Group.
HTH
Tea