Unable to install some old? packages

[Jan Palus]

# rpm --initdb --root=/pld
# rpm --import --root=/pld PLD-3.0-Th-GPG-key.asc
# poldek --root=/pld -uv filesystem
...
Processing dependencies...
filesystem-4.1-15.x86_64 marks FHS-3.0-7.x86_64 (cap FHS >= 3.0)
There are 2 packages to install (1 marked by dependencies):
A FHS-3.0-7.x86_64  filesystem-4.1-15.x86_64
Need to get 83.4KB of archives (83.4KB to download).

[1/2] th::FHS-3.0-7.x86_64.rpm [50.4K (50.4K/s)]                                 
[2/2] th::filesystem-4.1-15.x86_64.rpm [33.0K (33.0K/s)]                                
FHS-3.0-7.x86_64.rpm: digests OK
filesystem-4.1-15.x86_64.rpm: digests OK
Executing pm-command.sh --upgrade -vh --root /home/users/jan/pld --define _check_dirname_deps 0...
Verifying...                          ################################# [100%]
Preparing...                          ################################# [100%]
	package filesystem-4.1-15.x86_64 does not verify: no digest

Any idea what else is needed? Without importing gpg key it works fine, but why
it doesn't with gpg key?