Network down - timeouts << URGENT >>

[Typhoon]

We have a problem with our linux embedded-system and samba units.
We mount remote windows shared drives, and transfer a lot of file to/from 
them.
If Windows crash :) or unpluggin RJ, our program hang on read/write calls ( 
and all other access to remote file ) for undefined time...
WE NEED to set a SHORT timeout for connection lost !!!!!!
The sockopt  KEEP_ALIVE not help us! Is there some tuning to recognize 
netfail fairly?