I was also facing These gear shift problems also get my bike checked by service centre thrice for same problem but no use.
Later I observed this problem was only observed only when I half press clutch or not fully pressed.
Now no more more gear problem in last 3 months(brought in Sept 2012) In my case As I has developed habit to fully press clutch during gear change. Only drawback I feel is that it gives only 45-47 km/L in local.