The inside picking is refered to the way you pick betwen 2 strings like this:

e----0----1---3---5----7---8---10----12------
B------0----1---3---5----6---8----10-----12--
G---------------------------------------------

-----D-U-D-U-D-U-D-U-D-U-D-U-D--U--D---U---- (INSIDE PICKING)
-----U-D-U-D-U-D-U-D-U-D-U-D-U--D--U---D---- (OUTSIDE PICKING)

get the point?
Maybe its only the the way u start picking. :confused: