git fast-export | git fast-import doesn't work

Hi,

I would like to export our whole git repository to patches, and then reconstruct it again from scratch. Following the man page of "git fast-export":

$ git clone git://git.sympy.org/sympy-full-history-20081023.git
$ cd sympy-full-history-20081023
$ git fast-export --all --export-marks=marks > patches
$ cd ..
$ mkdir sympy-new
$ cd sympy-new
$ git init
$ git fast-import --export-marks=marks < ../sympy-full-history-20081023/patches
git-fast-import statistics:
---------------------------------------------------------------------
Alloc'd objects:      25000
Total objects:        21355 (       144 duplicates                  )
      blobs  :         8009 (         0 duplicates       4529 deltas)
      trees  :        10627 (       144 duplicates       9189 deltas)
      commits:         2719 (         0 duplicates          0 deltas)
      tags   :            0 (         0 duplicates          0 deltas)
Total branches:          21 (        26 loads     )
      marks:        1048576 (     10728 unique    )
      atoms:            726
Memory total:          2880 KiB
       pools:          2098 KiB
     objects:           781 KiB
---------------------------------------------------------------------
pack_report: getpagesize()            =       4096
pack_report: core.packedGitWindowSize =   33554432
pack_report: core.packedGitLimit      =  268435456
pack_report: pack_used_ctr            =      40706
pack_report: pack_mmap_calls          =       2791
pack_report: pack_open_windows        =          1 /          2
pack_report: pack_mapped              =   26177739 /   35513414
---------------------------------------------------------------------

However, the repository is very different to the original one. It contains only 191 patches:

$ git log --pretty=oneline | wc -l 191

and it only contains couple files. Compare this with the original repository:

$ git log --pretty=oneline | wc -l 2719

What am I doing wrong? Is there some other way to do it? I also tried "git format-patch" and "git am" and that almost works, only it changes hashes. Is there some way to tell "git am" to preserve the hash?

Thanks, Ondrej