In the folders panel Title, Click in the (+) Choose {Add Folder...}. In the popup dialog navigate to your Drive Desktop>Computer>..} If necessary mak a new folder in the EHD.
Before doing this, Give the drive volume a name
{Computer}{(EHD Drive Letter):\}{Properties}{General} This will help Windows to reassigne this Volume to the same drive letter each time you connect it. It will not prevent another removabable drive from claiming that letter making it unavailable to the EHD.