Account vouchers don't change period to the right company

When changing the company on a voucher it doesn't set the correct period for that voucher, so it will not be able to generate the move.lines necessary latter, I attached a patch for it (I can create a branch and submit a pull request if it is preferable):

=== modified file 'account_voucher/account_voucher.py'
--- account_voucher/account_voucher.py 2012-08-28 10:58:11 +0000
+++ account_voucher/account_voucher.py 2012-08-30 14:02:12 +0000
@@ -705,6 +705,16 @@
                 res[key].update(vals[key])
         return res

+ def onchange_company_id(self, cr, uid, ids, company_id, date, context=None):
+ if context is None:
+ context ={}
+ ctx = context.copy()
+ ctx.update({'company_id': company_id})
+ period_pool = self.pool.get('account.period')
+ pids = period_pool.find(cr, uid, date, context=ctx)
+ if pids:
+ return {'value': {'period_id': pids[0]}}
+
     def onchange_date(self, cr, uid, ids, date, currency_id, payment_rate_currency_id, amount, company_id, context=None):
         """
         @param date: latest value from user input for field date

=== modified file 'account_voucher/account_voucher_view.xml'
--- account_voucher/account_voucher_view.xml 2012-01-31 13:36:57 +0000
+++ account_voucher/account_voucher_view.xml 2012-08-28 22:27:44 +0000
@@ -47,7 +47,7 @@
                         <field name="journal_id" widget="selection" select="1" on_change="onchange_journal_voucher(line_ids, tax_id, amount, partner_id, journal_id, type)"/>
                         <field name="type" required="1"/>
                         <field name="name" colspan="2"/>
- <field name="company_id" widget="selection" groups="base.group_multi_company"/>
+ <field name="company_id" widget="selection" on_change="onchange_company_id(company_id, date)" groups="base.group_multi_company"/>
                         <field name="reference" select="1"/>
                         <field name="account_id" widget="selection" invisible="True"/>
                     </group>

=== modified file 'account_voucher/voucher_payment_receipt_view.xml'
--- account_voucher/voucher_payment_receipt_view.xml 2012-01-31 13:36:57 +0000
+++ account_voucher/voucher_payment_receipt_view.xml 2012-08-28 22:50:47 +0000
@@ -156,7 +156,7 @@
                         <field name="date" select="1" invisible="context.get('line_type', False)" on_change="onchange_date(date, currency_id, payment_rate_currency_id, amount, company_id, context)"/>
                         <field name="reference" select="1" invisible="context.get('line_type', False)" string="Payment Ref"/>
                         <field name="name" colspan="2" invisible="context.get('line_type', False)"/>
- <field name="company_id" widget="selection" groups="base.group_multi_company"/>
+ <field name="company_id" widget="selection" groups="base.group_multi_company" on_change="onchange_company_id(company_id, date)"/>
                         <field name="account_id"
                             widget="selection"
                             invisible="True"/>
@@ -309,7 +309,7 @@
                         <field name="date" select="1" invisible="context.get('line_type', False)" on_change="onchange_date(date, currency_id, payment_rate_currency_id, amount, company_id, context)"/>
                         <field name="reference" select="1" invisible="context.get('line_type', False)" string="Payment Ref"/>
                         <field name="name" colspan="2" invisible="context.get('line_type', False)"/>
- <field name="company_id" widget="selection" groups="base.group_multi_company"/>
+ <field name="company_id" widget="selection" groups="base.group_multi_company" on_change="onchange_company_id(company_id, date)"/>
                         <field name="account_id"
                             widget="selection"
                             invisible="True"/>