create an order w/o going to the payment gateway

I have several wholesale customers. I would like for them to be able to create an order without going to the Paypal gateway. I have activated the pay later option which they access through the control panel on the front end. Is there a way to change the next button on final stage of checkout to Make order or something to that effect? I have to calculate shipping after order is created and add shipping to the order after creation. Clear as mud? Thanks for all your help. Your product is very robust and I have been very happy with it thus far. Chip

Thank You for the links and quick response. You're great. However, I am not. Not a php warrior anyway. Not sure what I need to be doing here.

My checkout process is thus: cart_shipping_login_address,payment_fields_coupon_shipping_cart_terms_confirm,end.

At the last step before going to payment gateway, I need an additional button just for wholesale clients that says submit order or create order. Text not important here. What is important is that it creates the order as usual without sending wholesale clients to the payment gateway. Meanwhile, I need to leave the next button up for retail customer so they can proceed with payment. I appologize if you have covered this with the resources you have all ready supplied but I'm just not getting it. Thank You for your patience.