Dynamic channal creation from unit symbol to Dimension

While coding some dynamic channel creation i fail to create QuantityType channels.

Started with just a unit symbol W i managed to determine the Unit
Somehow i can’t figure out how to get form this Unit to a Dimension as String.

For instance:
W to Power so i can create a Number:Power channel

Unit<?> unit = Units.getInstance().getUnit("W");
assertEquals(Units.WATT, unit); // passes

Anyone with some suggestions?