Preview installs to existing instance

Hi there,

We have an existing instance of SAP on the server where we're installing full Sneak Preview. At Phase 2 of the install it attempts to create a new 'J2E' instance beneath the usr folder on the existing instance. However this instance doesn't have enough disk space...

How does one change this behaviour - ie. are there parameters to change in the install so that we can use another drive (which ironically has 156GB free!)

Thanks for your help.

Marc