Occurrences non-existant in Transaction

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Take an ITopicMap instance with at least one topic which in turn has at 
least one occurrence.
2. Create a Transaction from that ITopicMap.
3. Try to access an occurrence attached to a topic inside the transaction 
context.

What is the expected output? What do you see instead?
Instead of a set of occurrences one gets an empty set.

What version of the product are you using? On what operating system?
The issue occured using both the latest release (version 1.1.1) and the current 
revision in the hg repository (274).
I'm running Debian Sid (kernel 2.6.38-1-amd64) with openjdk-6 (version 
6b18-1.8.7-2). However, that's very likely not relevant to the issue.

Please provide any additional information below.
Taking a topic from the original topic map, getOccurrences() correctly returns 
a set of occurrences. Executing the same method taking the same topic from the 
transaction, an empty set is returned.

Original issue reported on code.google.com by [email protected] on 24 Mar 2011 at 1:46