It sounds like a number of girls have competed aerial cartwheel sideways on Beam, including Rhian Pugh from Wales and the great Corey Hartung in 2002.
Click PLAY or watch it on YouTube. (1min 8sec)
After competing and coaching at Florida, Corey went on to Cirque du Soleil.
Hailey Kardos in Canada was awarded an E-part for that skill in Canada.
Thanks Marcus.
Gymnastics Coaching.com 