Not the answer I needed but for anyone looking to remove the button.
{var i={DataId:"back-button",Icon:n?"Forward":"BackButton",DisplayText:Object(Ht.c)(this._resourceStrings,"Web.NavBar.Go_Back"),Id:qS.b,execute:t?null:e};a?this._prependedCommandList.push(i):this._addedCommandList.push(i)}
Removed this from apps.js it is buried in a line of code that is about 1000 characters. Search for back-button it only appears in this chunk of code.
The file is in C:\Program Files\Microsoft Dynamics CRM\CRMWeb\uclient\scripts
Hope this helps some one.