Unfortunately this is hidden axis stuf. Axis internally does a lot of copies, so you may want to take a look at your vm memory sizing and adjust it to be larger.
However there are some tricks you can do. You can bypass the rpc layer, and build your own message, or you can use attachments if you are sending alot of data.
If you really really care about performance, you could use something like JSR-173 to stream your message directly from a servlet.
We have a plan to start addressing performance in our rewrite.
Since we have .Net on the client side (attatchments compatibility?) and only one week left to acceptance test :) creating my own bulk message seams to be the only solution.
It seams as the soap response includes all attribute values for the sent objects instead of sending only changed (from default) values. This cloggs upp the message with a lot of default or null values which stands for at least 80% of the data... Very sad and very unnecessary spent cpu power.
Thanks for the tips!