Oracle Wallet is a finicky little tool. However, when you want to make outgoing HTTPS calls from the database, it's a necessary evil. While the tool itself is straightforward enough, the steps to follow in order to configure it are not as clear.
During my research, I came across what is perhaps the best step-by-step document for configuring Oracle Wallet that I have seen. Jeff Hunter's blog walks through the process in great detail, accounting for even the most minor of details. You can see his Oracle Wallet post here: http://www.idevelopment.info/data/Oracle/DBA_tips/PL_SQL/PLSQL_19.shtml
While this is definitely not something that I'll need daily, it's definitely getting bookmarked for the next time I'm faced with configuring Oracle Wallet.