SQLBULKCOPY function in .NET

Question

Hi, 

I am doing sqlbulkcopy from one table to another table.

There are so many tables to do that.
I am copying data with for loop for each tables.

But, i am facing with an issue, whenever i copy data from source table to destination table than identity column value is getting changed.

Suppoose there is value like this in identity column of a source table
301
305
605

but when i copy data than it will imported in destination table like that
1
2
3

1) I have tried,
set identity_insert [tablename] ON
//COPY Data from source to destination
set identity_insert [tablename] OFF