Sieve: file a mail into a shared folders subfolder

Hi there,

when I try to file mails into a shared folder (via OX), like this:

## Flag: |UniqueId:20|Rulename: move2sharedfolder-test
if header :contains "From" "test@test.com"
{   
    fileinto "shared/onlinezeitschriften@ourmaildomain.com/some-subfolder" ;
    stop ;
}

sieve log says:
error: msgid=<8d0866d4-583b-4c5c-92b3-22c177138d50@EX10CAS1.intern.gep>: failed to store into mailbox 'shared/onlinezeitschriften@ourmaildomain.com/some-subfolder': Mailbox doesn't exist: shared/onlinezeitschriften@ourmaildomain.com/some-subfolder.

I wonder if addressing a subfolder in shared folder is not supported in sieve, isn’t it?

Cheers
Sebastian