See if you can choose to not copy the Volume ID when cloning, or use an imaging app.
You can also use free Partition Wizard bootable CD to copy the source partition to deleted unallocated space while changing drive letter.
Then add the second OS using EasyBCD 2.0.
This has worked for me several times when imaging was too assertive with settings. All you need is an inert copy to add with EasyBCD.