If you want to fix config file jar in topology submission time, you might want to take a look at STORM-2016
It's in reviewing (already got some +1s) and will eventually be available. (hoping that it can be shipped to 1.1.0)
If you want to read config file jar in topology runtime (and read updated jar on demand), you could use BlobStore API which is available from Storm 1.0.0. Note that it will be treated as normal file, not one of classpath entries, so you need to handle it manually.
Please let me know if you have questions regarding above.
Jungtaek Lim (HeartSaVioR)