Use the Migration Manager account for all Migration-related tasks
During CM-migration from source to target sites the Migration Manager account is not entirely used. Instead, the machine account of the target site server is used to access objects and source files in the source site, like Images, Boot-Images and Driver Packages. Thus, when migrating cross Domian without AD-Trust, we cannot migrate these objects due to access errors. This is truly annoying. If the Migration Manager account from the source domain would be used consequently, there won't be this problem.