account_followup escaping % in text

when using the module account_followup, yous ometimes get a blank text printed on the followup report for the customer, if the text set contains the character '%'. That's because OpenERP tries to inject the partner's data and fails to do so. User should be warned at the time of creation/save of the followup text that there is a problem with what he has done.

to reproduce:
*create a followup line with text: 'we will charge you an extra fee of 10%'
*try to print that text for a customer matching the criterai you have set on the line: you will get blank text
*modify your followup line with text into 'we will charge you an extra fee of 10 percents'
*try to remind again your customer: it will work

so we should raise an error when the user created that line saying that the syntax is incorrect for '%' and that he has either to use an escaping character or the word 'percent'

Thanks