I am going to assume you are looking for an environmental mod for Stock SH4 1.5.
Here is a link that will get you started.
http://www.subsim.com/radioroom/down...o=file&id=1531
Super Mods like RFB, TMO and OM have their own environmentals incorporated into them so that if you load something else on top you will hose the MOD and its intent.
The complexities of these mods is such that they pretty much need to be run alone sans other additives.
Happy Hunting!