have a look at this tutorial: http://www.anddev.org/viewtopic.php?t=826
Its about DrivingDirections.
In there you'll find a line:
Using java Syntax Highlighting
this.myDD = new DrivingDirection(from_pos, from_name, to_pos, to_name);
Parsed in 0.011 seconds, using GeSHi
If I remember right, you can pass [font=Lucida Console]null[/font] to [font=Lucida Console]from_pos[/font] and [font=Lucida Console]to_pos[/font] and then pass a Location-describing String to the other params.
But I would not expect it to work very well. As the GeoCoder is not yet working properly.