Am I'm missing something or is the only way to move, copy or append a VAL to a different HAL is to offset it to a linestring and append that to a HAL. And that's okay I guess if your VAL has no vertical curves, but if it does the offset leaves you with a corded line that really makes a mess of the VAL it's appended to.
If it was possible to change the associated HAL in the VAL properties OR be able to copy and paste lines in the VAL editor (copy is an option but not paste?) OR be able to drag and drop to move VALs in the Project Explorer would solve this.
Edit: Actually simply appending doesn't work in most cases even with a VAL w/o vertical curves because it's appended to the end rather than just inserted.