I developed some Javascript functions to create a buffer around a point/current position. This script uses the UTM coordinates from the point, calculates the UTM coordinates of 360 points around it, converts them all to Lat/Lon and creates a text string to be used in the geoshape Calculate column. You will need to save the .txt file as .js because javascript attachments are surprisingly not supported here.
Please note that this script is not perfect and can be improved. It can also be used in a Repeat to create multiple buffers around the center point.
Daniel Dery