I found that I had to modify the the obround.ide file so that I can enter in
my own value. Here are the steps I took to modify the file.
1. open the obround.ide file
2. start the Edit iFeature command.
3. under the Size Parameters section change the Limit style from List to
None for the length and width parameter.
4. pick Apply
5. save and close the file.
Now when you insert the iFeature you will be able to enter in any size for