Store Procedures

Hello.
I been having "problems" with and application, and i want to store in
the data base the changes(update) made to a specific table.
what i need is to see how 2 fields specific change there values, to do
that i plan to make a temporal table with the fields before and after
plus the time the changes where made... can i do this with store
procedures??

here are the 2 fields are:
"cajas" INTEGER,
"unidades" INTEGER,

in the temporal table will be
"before_cajas" INTEGER,
"before_unidades" INTEGER,
"after_cajas" INTEGER,
"after_unidades" INTEGER,

Regards Cesar Alvarez.