Well, Jacob obviously does not use Guitar Pro 6 ... It is a really wonderful piece of software... but their manual is absolutely horrible. While the advice to "rtfm" is well taken, in this case it won't do much good.
But I digress. I wanted to share the somewhat convoluted method I have for inserting "numbers in circles" (guitar string numbers) into my scores. (I too have found no dedicated method in GP6 for doing this.)
A little disclaimer here. The method I use can only insert one single "circled number" into a score at a time. They cannot be "stacked" as in Ryans' example. So this solution will only work for a single note at a time.
My method requires two steps:
Step 1: Find a source to pick up the symbol I want... let's say ⑥ (six)
Step 2: Insert that symbol as "lyrics" into GP6.
For my "source" I simply used "Word Perfect 2013". In a new document, I clicked on the "Insert" menu icon, the used "Insert symbol" or "insert number" (far right side of menu) to find the circled number I wanted. Once I have it in WP2013, I can just highlight the character and copy it into the computer buffer (Control-C).
Then I go to GP6, click the little "Lyrics" microphone Icon (bottom on on left control-panel). and insert it (Control-V) there.
Granted there is a short learning curve on inserting lyrics into GP6... but it's not too bad. Mainly it's just figuring out how to space things to get the symbol where you want it.
I found this little YouTube video (produced by GP6 people) that gives the basics of inserting lyrics (in this case a "lyric" is a circled string number).
This solution is a little tedious... but it gets the job done (sort of).
Hopefully this capability will be added to GP7. We'll see.