[ic] Add weight to shipping

[interchange-users@interchange.redhat.com (Francisco Sánchez)]

Hello

I have created a new shipping method based on the Post Office rates, that
is, shipping by weight.

To the resulting rate I have to add a fixed amount which covers the
packaging.

No problem for this.  It can be done.

However I would also likte to add a fixed weight which covers the package
weight.  With this I mean that if I receive an order for a product that
weighs 990 grams, the shipping charges to any European country, according to
the post office rates, would be 6,95 Euro.  And this is the amount
Interchange will calculate.

However, since I have to add an "envelope", total shipping weight might be
around 1090 grams.  This means that the real rate charged by the Post Office
(for weights in excess of 1000 grams) would be 10,25 Euro.

Therefore a fixed weight of, say, 100 grams, should be added to each order
(not to each item, as in a single order, several items could be dispatched).

How to go about this?  I have searched and found no way to do this while at
the same time adding a fixed money amount to each order.

Regards,

Francisco