preseed file to partition the drive for a mixed lvm and non lvm fs

[Regid Ichira <regid23@nt1.in>]

  What should I write in a preseed file to get a HD partition with 
the requirments:

1. A 100G hard disk.
2. 50G are already in use by the first partition.  The installer
   should not do anything with that partition.
3. There is no partition defined for the other 50G.  Desired usage is:
   3.1. 1G for a /boot, $lvmignore, fs.
   3.2. 49G should be an $lvmok, $defaultignore. For all the other fs.
        That PV is devoted entirely to one VG.  And the VG consists of 
        a 40G home lv, and a single 9G lv for all the other fs.  No
        seperate usr, var and tmp.

I tried several recipes, but didn't find one that works.  I am not
sure I got the other variables correctly.  Should

    d-i partman-auto/init_automatically_partition select biggest_free

and the recipe suffice?