Unfortunately, without upgrading to 2013.1 and getting the improved unshelve operation, you're going to need to manually copy the data by:
- unshelving in trunk, noting the specific files that have changed
p4 edit
the files in your other stream/branch- manually copy the unshelved files to the other stream/branch (you can't use
p4 copy
orp4 integrate
for this because they aren't committed on the trunk - test and commit on the other branch