The parameters that are encryted are controled by the NonEncryptedParameters node in wc-server.xml. Adding the url parameters you want to stay in clear text to that node mean they don't get encrypted.
<NonEncryptedParameters display="false">
<Parameter name="storeId"/>
<Parameter name="langId"/>
<Parameter name="catalogId"/>
<Parameter name="categoryId"/>
<Parameter name="productId"/>
</NonEncryptedParameters>
I found the answer on IBM's Forum and a link detaling the use of the NonEncryptedParameters Node which talks about doing this for cache purposes.
David Waters
2009-08-20 09:00:18