How do I change the number of strings in Guitar Pro 6?

[Joppari]

I'm not sure does this fit in here or the computer hardware section, but I'll give it a try.
I want to change the number of strings to 4, and if it's possible I want the settings set as Mandolin.

[gnoob]

When adding a new instrument, go to exotic guitars and choose either banjo or ukulele, they're the only ones with 4 string options from what I can see, so I don't know how to get the mandolin setting working. Same thing though just sounds different right? Like the tuning should be the same and stuff so it should still work alright. I'm pretty sure that Guitar Pro 5 you could just choose how many strings you wanted to use though which is arguably better