2003 Plan Term Date-2004 Deduction ?

[JAY21]

A single employee (owner) plan terminates in late 2003. Plan is under funded. Since Funding Standard Account stops in 2003 is there any way to make a contribution for 2004 and claim a 2004 tax deduction ? The 2003 contribution was made and the 2003 corp. tax return filed, although he didn't contribute the 2003 max contribution available. He has since found more money he'd like to contribute in 2004 and deduct. What deduction options does he have for 2004 (if any) ? Thanks for any thoughts.