Maybe he meant "ST1". I thought a limitation of "V1" was that you could only draft parts, not assemblies. It also ran on the ACIS kernel. Heck that was 20 years ago and my memory is not that good!
Not exactly sure exactly what "it looses attachments to its parts\assemblys" means.
How about creating a Quick Sheet Template from the existing drawing and then drag in the new assembly.
Could you please upload a screenshot of your V1 with the actual problem...
Thank you everyone for your help!