Feature proposal: draw:escape-direction needs gluepoint with a combination of escape directions, e.g. left+up

draw:escape-direction is currently specified as one of auto, left,
right, up, down, horizontal or vertical.

a) There isn't the capacity to describe a a gluepoint with a combination
of escape directions, e.g. left+up

As an aside, this is something possible to select in OpenOffice.org's UI
and works correctly, but cannot be saved to ODF.