Keep current version with aptitude

[Sjoerd Hiemstra <shiems146@kpnplanet.nl>]

Hi,

Using Sid.
To keep a package at its current version during an
'aptitude safe-upgrade', I issue the command:

    aptitude hold <packagename>

But this only lasts for one upgrade.
During the next 'safe-upgrade' I am proposed to upgrade that package
again.

Is there a way to make it permanent?
In Synaptic there's an option to 'lock' the package. Is there an
aptitude equivalent?
I tried 'aptitude keep <packagename>' but apparently, that does not
achieve this either.

-- 
S.H.