Data modeler doesn't see packages created by "New item" menu

Description of problem:
First I create a new package by navigating to my project, the clicking New item > Package and entering my/cool/stuff. The I would like to define new objects using Data modeler. When I issue Data modeler > New Data Object the form that appears doesn't list my.cool.stuff among existing packages.

Version-Release number of selected component (if applicable):
DR6

How reproducible:
always

Steps to Reproduce:
1. go to uf-playground / mortgages, create new package my.cool.stuff (you have to type "my/cool/stuff" as the File Name)
2. open Data modeler and bring up the "Create new data object" dialog

Actual results:
The Existing package select box doesn't contain my.cool.stuff package.

Expected results:
It should be possible to select my.cool.stuff from Existing package select box

Additional info: