Infopath 2007 + SQL 2005 submit issues

I am designing a Purchase Order form with InfoPath 2007 that will be
submitted to SQL 2005. I set up the tables necessary in SQL and created my
form with those fields. I need a sequential numbering system to act as the
PO number for every form. I decided to use SQL to generate the numbering for
me so I set up the Identity Specifications:
with a primary key that is a tinyint,
identity specifaction- yes
is identity-yes
identiy increment- 1
identity seed-1
not for replication-no

When I go and fill out my form to insert a new record and click submit I
recieve the following error:

"Cannot insert explicit value for identity column in table 'POVenderInfo'
when IDENTITY_INSERT is set to OFF."

I tried to turn in on in SQL and it told me it executed successfully,
however, I retried the form again and it did not work. Is there a setting
that must be changed in InfoPath in order for this to submit properly? If
not, what must be done to fix this problem?

Thanks ahead of time