there's some documentation for it on the old 2D wiki - I've not looked at it yet & I think it is based on an older version, but it might offer you some more insight into how the particle system works
" target="_blank">here is all the documentation listed in a single page for the old wiki. there's a mix of English & German documentation - I think the particle system is covered in German too - just browse down the page.
** hmm it's not liking the link: http://wiki.visionaire2d.net/index.php?title=Special
: PrefixIndex (join it all together)