Expressing result in defined unit

Hello, I am a new user to MathCAD, and after searching other posts a bit I am still at a loss of how to express my results in a unit that is not available by inserting a custom unit. What I would like is to have my results expressed as "Msi". I can define the unit of Msi as 1*10^6 psi, but my results -- albeit correct -- are still displayed in psi. for example, if I defined M:= 42 Msi, the answer is expressed as M=42*10^6 psi. What I would like it to display the result as is "M=42 Msi". Is there a way to do this? Thanks for any help.