Change "database system identifier" in pg_control?

Hello everyone,

I'm trying to change the SYSID in pg_control (at least I think that is
where it is) due to a catastrophic backup system failure, combined with
a timely administrative "oops". Does anyone know how I might go about
doing that?

The back story, for those interested:

We lost *all* of our recent backups due to massive hardware failure. A
new database was added within the last couple of weeks and yesterday
morning one of our admins toasted it. We've got a pg_dumpall from after
the database was created and all of the archive logs since. I was trying
to recreate the whole system on another machine to attempt restoration
of the data. The first problem that I ran into was the checkpoint was
incorrectly set (due to the system being a new installation). I was able
to fix that (I think) with the pg_resetxlog command but a subsequent
recovery attempt yields the following errors in the log:

2006-12-14 22:42:09 MST LOG: restored log file
"000000010000002300000079" from archive
2006-12-14 22:42:09 MST LOG: WAL file is from different system
2006-12-14 22:42:09 MST DETAIL: WAL file SYSID is
4965793265546637307, pg_control SYSID is 5008561987249897439
2006-12-14 22:42:09 MST LOG: invalid primary checkpoint record
2006-12-14 22:42:09 MST LOG: invalid secondary checkpoint link in
control file
2006-12-14 22:42:09 MST PANIC: could not locate a valid checkpoint
record
2006-12-14 22:42:09 MST LOG: startup process (PID 15145) was
terminated by signal 6
2006-12-14 22:42:09 MST LOG: aborting startup due to startup process
failure
2006-12-14 22:42:09 MST LOG: logger shutting down

So I thought I would try to change the SYSID to 4965793265546637307 and
have another shot at it.

I'm not a PG guru so please let me know, is there any chance that what
I'm doing will be successful, or am I just wasting my time?

Thank you very much for any help you can provide!

--
Joshua Colson <joshua(dot)colson(at)ination(dot)com>
iNation, LLC