Upgrade from SAP integration XI R2 to XI 3.1

Hi,

We are currently using BOXIR2 and SAP kit XI R2. We are planning to upgrade to BO XI 3.1.

Question-

1. We want to upgrade the kit to XI 3.1 ? what should be the process for upgrading?

a. Should I uninstall XI R2 kit and install XI 3.1 kit after BO XI 3.1 installation or is there a option for upgrading from XI R2 kit to XI 3.1?

2. SAP kit works only with .NET or Java as well?

Thanks....