How to insert identity values into an identity column

Just try it and you'll get:

Msg 544, Level 16, State 1, Line 6
Cannot insert explicit value for identity column in table 'YourTable' when IDENTITY_INSERT is set to OFF.

So simply:

SET IDENTITY_INSERT YourTable ON

INSERT sometableWithIdentity (ID, col2, col3, ...)
VALUES (33, 'fred', 'smith', ...)

SET IDENTITY_INSERT YourTable OFF

But first:

Have you tried not explicity setting a value for the identity column?