Automated rotation(Excel)

Hi All,
I would really like to automate a process of rotating arrows and using them as markers to indicate direction into an excel line graph.
I already have an array to convert bearing to a numerical one i.e. South = 180
From there i would like excel to create an arrow and rotate it to that direction, (upward on the screen being north). Preferably in the cell adjacent to the bearing.
And ultimately i need to put these into a graph where the points are equivalent to a wind speed, like the picture below.
Any help would be muchly appreciated.
Thanks,
Dan

http://img38.imageshack.us/img38/549...ionalgraph.png