Why I lost the last pg_xlog file?

Hi,

Yesterday I perform a crash test, but I lost the last pg_xlog file.
Let me explain:

First I did the pg_start_backup
Second I copied the phisical files to the slave server
Third I did the pg_stop_backup

So I run a test,

1) In the master server I created a 100.000 records table
2) I Runned the "checkpoint" command to be sure the table will be saved.
3) I check the pg_xlog, there was created 6 logs, but in the archive
there was only 5.
4) I copied the achives files to the slave server and I created a
recovery.conf and started the slave postgres.
5) Postgres recovered the 5 log files correctly,  but the new table did
not came to the slave. I think because the last pg_xlog file was not
archived.

I did not understand why the last file wasnt archieved?
There is a command to be sure all pg_xlog is archived? or I need to copy
the last file to the slave before recovery?

How is the correctly way to perform a recovery in this case?

Thanks,

Waldomiro Caraiani