[galaxy-dev] How to get the encoded ID from the HistoryDatasetAssociation?

I'm really close to having a way to visualize radiological images in Galaxy, but need help in getting past the final hurdle.

In the mako file, I can see how to pass parameters to the javascript that does the visualization. It's expecting a URL to the dataset, like:

params["images"] = ["/datasets/78176dfc865c8302/display/"];

From what I can gather 78176dfc865c8302 is the encoded ID for the dataset. From variables like hda.name and hda.id I can see various properties of the

dataset, but not the encoded ID.

Any suggestions on how to do this?

Thanks in advance.

Malcolm