Copy job troubles

Hello.

I've got a system where I have two NAS storages and one HD based virtual 
autochanger.

Clients do nighly backups on either NAS.
Weekly I copy Fulls and Diffs to HDs (on the third storage).

However, copy jobs from NAS A to HD work, while copy jobs from NAS B to 
HD don't.
First they output the following warning:

> Warning: Could not find a compatible Storage to read volumes in the TBackupB Job definition (StorageB/File)

then they ask me to mount the volume (which is on NAS B) on NAS A.

I've tried and tried, but I cannot find the reason why the correct 
storage is not picked up.
I'm pasting below an extract of my config: does anyone see what's wrong 
in it?

  bye & Thanks
	av.

-------------------> Storage {
>   Name=StorageA
>   Address=...
>   Password="..."
>   Device=BackupA
>   Media Type=File
> }
> Storage {
>   Name=StorageB
>   Address=...
>   Password="..."
>   Device=BackupB
>   Media Type=File
> }
> Storage {
>   Name=HDChanger
>   Address=...
>   Password="..."
>   Device=HDChanger
>   Media Type=File
>   Autochanger=yes
> }
> 
> Pool {
>   Name=FullA
>   Pool Type=Backup
>   Storage=StorageA
>   Next Pool=ExtHD
> }
> Pool {
>   Name=FullB
>   Pool Type=Backup
>   Storage=StorageB
>   Next Pool=ExtHD
> }
> Pool {
>   Name=ExtHD
>   Pool Type=Backup
>   Storage=HDChanger
> }
> 
> JobDefs {
>   Name="DefaultJob"
>   Type=Backup
>   Level=Incremental
>   Client=...
>   FileSet="Catalog"
>   Schedule="Weekly"
>   Storage=StorageA
> }
> 
> Job {
>   Name=DBackupA
>   JobDefs="DefaultJob"
>   Full Backup Pool=FullA
> }
> Job {
>   Name=DBackupB
>   JobDefs="DefaultJob"
>   Full Backup Pool=FullB
>   Storage=StorageB
> }
> Job {
>   Name=TBackupA
>   JobDefs="DefaultJob"
>   Type=Copy
>   Selection Type=SQLQuery
>   Selection Pattern="SELECT * FROM (SELECT jobid,level,endtime FROM job WHERE name='DBackupA' AND level='F' AND jobstatus='T' AND poolid!=7 ORDER BY endtime DESC LIMIT 1) AS f UNION SELECT * FROM (SELECT jobid,level,endtime FROM job WHERE name='DBackupA' AND level='D' AND jobstatus='T' AND poolid!=7 AND endtime>(SELECT max(endtime) FROM job WHERE name='DBackupA' AND level='F' AND jobstatus='T' AND poolid!=7) ORDER BY endtime DESC LIMIT 1) AS d"
> }
> Job {
>   Name=TBackupB
>   JobDefs="DefaultJob"
>   Type=Copy
>   Selection Type=SQLQuery
>   Selection Pattern="SELECT * FROM (SELECT jobid,level,endtime FROM job WHERE name='DBackupB' AND level='F' AND jobstatus='T' AND poolid!=7 ORDER BY endtime DESC LIMIT 1) AS f UNION SELECT * FROM (SELECT jobid,level,endtime FROM job WHERE name='DBackupB' AND level='D' AND jobstatus='T' AND poolid!=7 AND endtime>(SELECT max(endtime) FROM job WHERE name='DBackupB' AND level='F' AND jobstatus='T' AND poolid!=7) ORDER BY endtime DESC LIMIT 1) AS d"
> }

P.S.
I also tried adding "Storage=StorageB" to TBackupB job definition, but 
it did not help.
However it works if I run the job manually and explicitly specify 
(source) pool and storage.