In order to make it easier, I configured ISE with an IP on the same VLAN as the ACS (you can change ISE IP to the right one later) and I followed the next steps (like a checklist).
1.-Decide what type of migration SIMPLE or ITERATIVE - On my case, it was ITERATIVE
2.-Enable Policy Sets on ISE (check again video - manual guide)
3.-Enable Device Admin Service (check again video)
4.-Evaluation License on ISE can be used.
5.-Change Policy Set Name on ACS and change the name so they do not overlap the default ones on ISE
6.-Change Service Selection Rules Name on ACS so they do not collide with ISE default ones
7.-Compare once migrated the number of ACS:
#devices
#service selection rules
#command sets
#authorization profiles
#internal users
8.-Use ACS superadmin account for the migration (mandatory)
9.-Add ACS and ISE self signed cert to the migration tool
10.-DNS Entry for ACS and ISE in production
11.-Install ACS self-signed cert into the ISE Trusted Certificate list.
12.-Install ISE self-signed cert into the ACS Trusted Certificate list.
13.-Install permanent TACACS license on ISE (after the migration)
14.-Configure the LAN Switch where the Win 7 Laptop running the migration tool, the ACS and ISE will reside.
15.-From CLI, enable migration on ACS and ISE (both). Check video.
On ISE: application configure ISE option 11, then type 0 to exit
On ACS: acs config-web-interface migration enable
C:\Program Files\Java\jre7\bin\javaw.exe
http://java.sun.com/products/autodl/j2se
