如果产品转到付款方式，则禁用特定网关进入结账：是“支票付款”

I try to explain better and fast what I did and what I need.

I forced to do "Cheque Payment" for some certain products, because before to give the possibility to pay the order I need calculate some values and add the relative shipping cost.

So this is what happen, the customer do the order, he do the "cheque payment", I review the order, I add the shipping cost and then I set the order in "Pending Payament". At this point, when the customer receive the email and go to open the checkout page to pay the customer have the possibility to do again the "cheque payment" and I need remove this possibility.

So I need disable the "cheque payment" gateway when into the checkout page, the order, have the voice "Payment Method" with the value "Cheque Payament"

Can you help me?