Link Opportunities and Invoces tables in ZOHO CRM

Link Opportunities and Invoces tables in ZOHO CRM

One major problem in ZOHO CRM is the lack of link between Opportunities and Invoces. Imagine you need to add informations from the opportunities tables into an invoce....Then you can not do it unless you add again this (these) field(s) in the invoces table and have then double entry....
The most bizarre is that Opportunities and Quotes tables are linked (you can add a field from opportunities into quote) and you have the ability to transform a quote into invoice but then you loose some informations.
I am stucked with this and do not want to rewrite the hole application and/or export the two tables and make the treatment outside ZOHO CRM
 
Any idea ?
 
Regards
 
Please note I am using this application in France/french and that I have to deal with products with different VATs on same invoice sometimes