NetBackup 7.6 Duplication and then Replicate exceeds maximum backup copies allowed

Hello

Hope someone can help

In NetBackup 7.6 using Storage Lifecycle Policies can you first backup to disk, then duplicate to tape ready for offsite collection. Then replicate the data to another site?

I have successfully done a test and can backup to disk and replicate to a remote site but I cannot duplicate as I get the following error

" Number of storage operations exceeds the maximum backup copies allowed".

How can I backup to disk, duplicate then replicate my data? also does this support synthetic full backups?

Thanks in advance