How do 'transportable tablespaces' work in 11g-ASM for a manual TSPITR?

At the moment we are doing some restore tests in 11g and ASM. We try to use old scripts which we used before we moved to 11g and ASM for the last time. Now there appeared some problems with TTS (Transportable Tablespaces) after a manual TSPITR of a single tablespace into an auxiliary database. In our old script the procedure was roughly the following:

1. export the metadata of the tablespace from the auxiliary database

2. copy the datafiles from the auxiliary database directory to the original database directory

3. import the metadata in the original database

Now, in ASM and with Oracle Managed Files the copy in 2. is not so easy any more. You are not allowed to set the file/incarnation number of the target datafile in the ASM cp command. In fact, you may leave this number away. But then, the result of the cp command is only an alias name in the desired ASM directory whereas the real file is somewhere else. This does not really hurt but, it is unpleasent. One datafile is different to all other datafiles in the target database.