Hello,
why don't you take a look at my Lamborghini Cars website, on the main page you have a link to Workshop manuals and Parts manuals, this page offers you a selection of two websites that actually offer these manuals for sale.
My site is located at :
http://www.lambocars.com
Also a very good source is the Jalpa homepage from a good friend of mine, Raymond Stofer, he actually has the manual online, so you can browse it, take a look at :
http://www.jalpa.ch
I hope you can solve the problem,
kind regards
Mark