Yes, the VX-427 will work on the 70 cm band. You don't need to modify the CE-64 software. You just need to run it in 'Manufacture Mode', which will let you change the lower band limit to 440 MHz, or whatever you want.
The MaxKelley.com website explains the steps needed to do this for some other Vertex Standard software, but basically, right-click the CE-64 icon on your desktop and then click on Properties. Add (space)-m to the right end of the Target line.
When you run CE-64, it will start with a password box. Enter ansho-bango as the password.
From the menu line, you can navigate to the Common...Hardware screen and change the minimum frequency to 440 MHz.