Cost Plus and fixed Price

 Project Experts,

I have business requirements to create two projects  first with fixed price and second with cost plus. Has any one did this and would like to share there expertise would be great.

Here are details.

For cost plus the business need is to create a project with transactions that applied a markup over the cost percentage.  Any one did this do you know how you applied mark up over the cost %

For Fixed cost create a project with transactions that will create an automatic (additional line) with flat fees?

Many thanks in advanced for your time

Aijaz