Help for shipping cost "customized!"

Hello,
one of my customer asks me to make the following two different options:

1. Selecting "cash on delivery" the shipping cost is always 12 euros.
2. For any other type of payment (not "cash on delivery") the shipping cost is 12 euros only for orders below 100 euro.

Is it possible to make this without modifying the source code? Otherwise, what do you suggest me to modify?

Thanks!

The problem is that Shipping Method needs to be selected before payment method (because after payment method selection the next step is payment - the total amount depends on shipping method selected).

You don't say what the shipping cost is when other type of payment (not "cash on delivery") and order is greater than or equal to 100 euro.

If you were to, for example, have only shipping rates:  COD is 12 euro , and Credit Card is 10 euro, then this can be done with Payment Director if you are OK showing the payment method name as the shipping method name - i.e. they effectively select the payment method at the same time they select the shipping method:

Setup two Shipping Methods
  Cash on delivery shipping
  Regular shipping

Setup Shipping Rate Calculation Method "Fixed Rate Shipping" for the above two methods.

Configure Payment Director to only show COD payment method if they selected "Cash on delivery shipping":

  Option  Payments.CashOnDelivery         ShippingOptionName = "Cash on delivery shipping"
  Option  Payments.AuthorizeNet           ShippingOptionName != "Cash on delivery shipping"

Depending on your requirements for when order is greater than or equal to 100 euro, you may also need to use Shipping Director