vspider and agentname

I use vspider with a command file for indexing my collections. To differentiate between languages on my website I use session variables, as this does not work with the spider, I name the spider accordingly with -agentname e.g spiderFrench, spiderGerman. Depending on the spidername I serve the page in the chosen language. (the URL is always the same for a page - not matter what language is requested). Unfortunately only my main lanaguage is indexed !
My log files tell me, that when vspider comes through collecting the URLs it uses my given agentname, but when it comes through actually indexing the page it uses it's own agentname verity-URL-Gateway and so it will always index my default language. Is there a way I can influence / overwrite veritys user-agent ?