import maya.cmds as cmds
curctx = cmds.currentCtx()
if cmds.superCtx(curctx, ex=True):
ctx = cmds.superCtx(curctx, q=True)
# This appears to work
cmds.manipMoveContext(ctx, e=True, orientAxes=[0,20,-45], mode=6)
# So does this
cmds.manipMoveContext(ctx, e=True, orientObject='pConeShape1', mode=6)