Problem with SSIS and auto-increment of an ID

Hello,
I have a little problem with SQL Server 2005. I have chosen the option "auto-increment" for a column which includes the primary key. Moreover, I turned the option "Ignore double values" on. I get the datasets from a SSIS-Import-project. Unfortunately, the ID is getting incremented even if there are double values.
For example:
The first entries in the table have the IDs: 1, 2, 3, 4, 5
Then I start the SSIS-project which tries to write the first 5 entries again in the database. Of course, the entries do not appear again in the db but a new entry gets the ID 11 instead of 6. Is there a setting, that the ID won't get incremented if there double values?
Thanks
M-l-GI have not used the "auto-increment" function but the only time I had to increment a value was when the field was a key in my db. I set the key as an Identity key and so the db takes care of the incrementing. Is this something you are able to do? Just a thought!sql