pattr does not bind to all objects?

Hi there.
I am trying to do a very simple thing: I want to port a bunch of floats packed into a list (using [pak]), from one patch to another patch using [pattr] bindings. There should be no problems with the bindto path etc., since I can bind floats/integers individually. But, when trying to bind to [unpack] or [unjoin] or for that matter a [number~] I get the "failed to bind to target" - also when trying to bind in the same patch. Does pattr not recognize/bind to all objects? Have I misunderstood something here, is pattr only for Max UI-objects?
Haven´t tried yet, but could possible use patrhub and break the receiver-patch up into individual pattr/floats? Was however trying to get rid of as many objects and streams as possible. Or use send/receive....... -but not so elegant as pattr.
If anybody has a suggestion, it would be appreciated very much.
Greetings Ras