odoo/addons/account/account_invoice_workflow.xml

<?xml version="1.0"?>
<terp>
<data>
	<record model="workflow" id="wkf">
		<field name="name">account.invoice.basic</field>
		<field name="osv">account.invoice</field>
		<field name="on_create">True</field>
	</record>

		<record model="workflow.activity" id="act_draft">
			<field name="wkf_id" ref="wkf"/>
			<field name="flow_start">True</field>
			<field name="name">draft</field>
		</record>
<!--		<record model="workflow.activity" id="act_confirm">
			<field name="wkf_id" ref="wkf"/>
			<field name="name">confirm</field>
		</record> -->
		<record model="workflow.activity" id="act_sale">
			<field name="wkf_id" ref="wkf"/>
			<field name="name">sale</field>
			<field name="action">action_move_create()&#10;write({'state':'sale'})</field>
			<field name="kind">function</field>
		</record>
		<record model="workflow.activity" id="act_proforma">
			<field name="wkf_id" ref="wkf"/>
			<field name="name">proforma</field>
			<field name="action">action_move_create()&#10;write({'state':'proforma'})</field>
			<field name="kind">function</field>
		</record>
		<record model="workflow.activity" id="act_open">
			<field name="wkf_id" ref="wkf"/>
			<field name="name">open</field>
			<field name="action">action_move_create()&#10;action_number()&#10;write({'state':'open'})</field>
			<field name="kind">function</field>
		</record>
		<record model="workflow.activity" id="act_paid">
			<field name="wkf_id" ref="wkf"/>
			<field name="name">paid</field>
			<field name="flow_stop">True</field>
			<field name="action">write({'state':'paid'})</field>
			<field name="kind">function</field>
		</record>
		<record model="workflow.activity" id="act_cancel">
			<field name="wkf_id" ref="wkf"/>
			<field name="name">cancel</field>
			<field name="flow_stop">True</field>
			<field name="action">action_cancel()&#10;write({'state':'cancel'})</field>
			<field name="kind">function</field>
		</record>

		<!--
		<record model="workflow.transition" id="t1">
			<field name="act_from" ref="act_draft"/>
			<field name="act_to" ref="act_confirm"/>
		</record>
		-->

		<record model="workflow.transition" id="t2">
			<field name="act_from" ref="act_draft"/>
			<field name="act_to" ref="act_sale"/>
			<field name="signal">invoice_sale</field>
		</record>
		<record model="workflow.transition" id="t3">
			<field name="act_from" ref="act_draft"/>
			<field name="act_to" ref="act_proforma"/>
			<field name="signal">invoice_proforma</field>
		</record>
		<record model="workflow.transition" id="t4">
			<field name="act_from" ref="act_draft"/>
			<field name="act_to" ref="act_open"/>
			<field name="signal">invoice_open</field>
		</record>
		<record model="workflow.transition" id="t5">
			<field name="act_from" ref="act_proforma"/>
			<field name="act_to" ref="act_open"/>
			<field name="signal">invoice_open</field>
		</record>
		<record model="workflow.transition" id="t6">
			<field name="act_from" ref="act_sale"/>
			<field name="act_to" ref="act_paid"/>
			<field name="trigger_model">account.move.line</field>
			<field name="trigger_expr_id">move_line_id_payment_get()</field>
			<field name="condition">test_paid()</field>
		</record>
		<record model="workflow.transition" id="t7">
			<field name="act_from" ref="act_proforma"/>
			<field name="act_to" ref="act_paid"/>
			<field name="trigger_model">account.move.line</field>
			<field name="trigger_expr_id">move_line_id_payment_get()</field>
			<field name="condition">test_paid()</field>
		</record>
		<record model="workflow.transition" id="t8">
			<field name="act_from" ref="act_open"/>
			<field name="act_to" ref="act_paid"/>
			<field name="trigger_model">account.move.line</field>
			<field name="trigger_expr_id">move_line_id_payment_get()</field>
			<field name="condition">test_paid()</field>
		</record>
		<record model="workflow.transition" id="t9">
			<field name="act_from" ref="act_draft"/>
			<field name="act_to" ref="act_cancel"/>
			<field name="signal">invoice_cancel</field>
		</record>
		<record model="workflow.transition" id="t10">
			<field name="act_from" ref="act_sale"/>
			<field name="act_to" ref="act_cancel"/>
			<field name="signal">invoice_cancel</field>
		</record>
		<record model="workflow.transition" id="t11">
			<field name="act_from" ref="act_proforma"/>
			<field name="act_to" ref="act_cancel"/>
			<field name="signal">invoice_cancel</field>
		</record>
		<record model="workflow.transition" id="t12">
			<field name="act_from" ref="act_open"/>
			<field name="act_to" ref="act_cancel"/>
			<field name="signal">invoice_cancel</field>
		</record>
</data>
</terp>