Force the id value

I'm trying to migrate a lot of values from a database (MS Access mdb
via odbc) to another mysql database (from which I'll start to build a
RoR based application), using the ruby-odbc library I can access the
datas in the mdb file, I would like that some important things, like
the ids in the tables, will be the same in the two databases (all the
foreign keys are already set in the mdb, so why do I have to compute
them again?), table structure will be a bit different, the mysql based
one will be more refined than the old software one, but most of the
structure could be inherited from the mdb one.
Thus I'm looking for a way not to waste all the informations that are
already present, a.k.a. the joins already in place (without having to
use two ids, the rails one and another field for the referenced one,
this looks clumsy to me...).

Thank for the answer

Really none has had this problem?

Probable solution, but it don't look like so clean, is to use the

SomeModel.connection.execute("UPDATE tablename SET id='3' WHERE id='5'")

Updating works, now I try with an insert...


Sorry for the "look like" in the previous post.. O_O

However the execute("INSERT... works as expected... this is probably
the only way.