I was trying to do this inside the Family Editor by opening up a Generic Annotation Family and then importing the AutoCAD drawing of my stamp into the family. I made sure the import dialog had a custom scale of 1:1, set the selection to B&W and Center to Center. Hit OK and then nothing. Blank display with no drawing apparently present. I check the list on the Undo Pull Down and it indicates the drawing has been imported. All kinds of zooms and checking the View Graphics modes and whatever yield to drawing whatsoever.
So...I give up on that. I try importing the stamp drawing into just a project. A-HA! It comes in, albeit not too recognizable. I think it has something to do with the fact that I am running screen resolution of 1600x1200 on a 19" screen. Whatever! So...I say to myself...I'll just copy this thing to the clipboard, open up the Generic Annotation Family again and paste it. NO DICE! A not allowed error! How stoopud is this!
Anyway...I finally got the stamp done inside the Family Editor. The idea that polar arrays are not allowed inside there is still a STOOPUD concept to me. Why not? What's it gonna' hurt? If I want to array sumpin'....let me array it! FRUSTRATING!!!
What I ended up doing was to generate some guidelines around the top and bottom of the expected text height (circles) and also mirror copying some radial lines from the center of the circle to the outer guideline circle. I then placed the first text object, copy-rotated it to the new position for the next letter, and edited it for angle of rotation. Repeating this for all 36 letters finally got the job done! SHEESH!
Another thing! What is with this program NOT mirroring text angles in relation to the opposite angle it was set, ala AutoCAD! If you set a text object at 45 degrees in AutoCAD and mirror it, the new text object sits at 135 degrees....a true mirror! NOT REVIT! What's up with that?