With the ResourceLocator this property is obsolete, I think.
hmm, strange because OBJ models do support the setProperty() method (for materials and textures). Furthermore, because the path is in the model itself the ResourceLocatorTool cannot find the texture, the ResourceLocatorTool uses the path that is included in the model (for blender it happens to be an absolute path). Notice in the output above how the ResourceLocatorTool reports it can't find the image at "c:Eclipse…" this path was in the model and NEVER was on my computer. Below that is a print of the path that the game logic creates, it is correct.
I have found a workaround by manually text editing all the ASE models and removing the path (leaving only the filename) and the texture is found no problem. However, this is quite a pain since any change in any model requires that model to be text edited and with a tile based game there is a LOT of models.
It should be able to find the texture even with an absolute path (works over here with 3ds, at least). Seems you need to debug a little more, why it does not work in your case.
Many of the converters are switched to use ResourceLocatorTool… But not all, it looks like. Obviously this is something that needs to be standardized.
hmmm, well I did some more debugging 
(this was in addition to the couple of hours of previous debugging) and I don't think the problem is on my end.
Try adding c: to the BITMAP path in statue.ase (the one from jME test data) you will see that it does not find the texture; however if you add /volumes/temp it DOES find it.
This is OSX or Windows…