awk '
NR==FNR {
   split($0, cfg, /,/);
   config[cfg[1]] = cfg[2];
   next;
}
$5~/^document/ && ($NF in config) {
  $NF = config[$NF];
}
1
' B A

awk '

NR==FNR {                           # Select records from first file
   split($0, cfg, /,/);             #    Split record with "," into record cfg
   config[cfg[1]] = cfg[2];         #    Memorize config value
   next;                            #    Proceed next record
}                                   #

# The following code is for second file
                                     
$5~/^document/ && ($NF in config) { # Select records starting with "document" and
                                    #  last fields memorized in config record (build
									#  from first file)
  $NF = config[$NF];                #    Set last field with corresponding value from config array
}                                   #
 
1                                   # Print record (maybe modified above)

' B A