Allow conditions on multiple tables to be specified using hash.: BUG?

I'm working with a legacy MSSQL database with non-traditional table
names and foreign keys. For our purposes tablel 1 is named 'tblFoo"
and table 2 is named "tblBar". I named the models for the before
mentioned tables foo.rb and bar.rb, using set_table and
set_primary_id. Foo has_many :bars and bars
belongs_to :foo :foreign_key => 'fldBarID

In the process of performing a find with conditions on the two tables
I produced the following code:

@Foos = Foo.all(:include => :bars, :conditions => {:id => '25', :bars
=> { :created_on => '11/06/2002'}})
@Foos = Foo.all(:joins => :bars, :conditions => {:id => '25', :bars =>
{ :created_on => '11/06/2002'}})

...and the above code produces the following error:

ActiveRecord::StatementInvalid: DBI::DatabaseError: 37000 (4104)
[unixODBC][FreeTDS][SQL Server]The multi-part identifier
"bars.created_on" could not be bound. The error is caused when rails
does not replace the :bars symbol with the correct table name
(:tblBar) in WHERE section the generated sql. (but the table name is
correctly produced in the INNER JOIN section).

However.... if I format my find as follows, its all good (note the
symbol tblBar in the conditions with is the literal table name)

@Foos = Foo.all(:include => :bars, :conditions => {:id =>
'25', :tblBar => { :created_on => '11/06/2002'}})
@Foos = Foo.all(:joins => :bars, :conditions => {:id => '25', :tblBar
=> { :created_on => '11/06/2002'}})

Naming the models after the tables like tbl_foo.rb produces the same
error describe above and so does creating the has_many association:

has_many :tblBar, :class => 'bar'

Is this a bug in the find or the MSSQL driver?

Just for reference: