Is by any chance you try those supliers

http://www.4starelectronics.com/

http://www.hkinventory.com/public/Home.asp


VN540 will be the replacement part

datasheet:
http://www.angliac.co.uk/st/data_from_st/6010.pdf

distributors:
http://www.st.com/stonline/address/distrib/index.htm

i found some at Arrow.com for few $

regards