Stephen Hemminger wrote:

+arp_notify - BOOLEAN
+	Define mode for notification of address and device changes.
+	0 - (default): do nothing
+	1 - Generate gratuitous arp replies when device is brought up
+	    or hardware address changes.

Did you consider using gratuitous arp requests instead?  I remember 
reading about some hardware that updated its arp cache on gratuitous 
requests but not gratuitous replies.

Chris