Amazon External Links (no replies)

Hello

I am using piwik on a brand new website of mine.
I'd like to generally track the clicks to amazon.com and its domains containing the word amazon.
I've got a wordpress plugin that does geo redirect for amazon domains, so that's I want to use amazon word.
My present settings for a goal are:

Goal Name:
Amazon clicks

Goal is triggered:
Click on a Link to an external website

where the external website URL
contains amazon

Allow multiple conversions per visit
Allow Goal to be converted more than once per visit

I've tested the settings with either contains, is exactly or matches the expression. None of them registered.

However, I've got two other clicks tracking going, which are the following:

----------------

Goal Name:
Twitter Clicks

Goal is triggered:
Click on a Link to an external website

where the external website URL
is exactly https://www.twitter.com/mytwittername

Allow multiple conversions per visit
Allow Goal to be converted more than once per visit

-----------------------

Goal Name:
Facebook link clicks

Goal is triggered:
Click on a Link to an external website

where the external website URL
Is exactly https://www.facebook.com/mypage

Allow multiple conversions per visit
Allow Goal to be converted more than once per visit

========

These 2 work.

How could I set the amazon link clicks setup? I use no redirection, so all links are direct to amazon domains. So no mydomain.com/amazonlink, just old amazon.tld/bla?tag=myassid=20 .

I would be interested in a format like in the examples here:
eg. contains 'amazon.com'
eg. is exactly 'http://mypartner.com/landing.html'
eg. matches the expression 'http://www.amazon.com/(.*)/yourAffiliateId' <=== especially that one

Thanks you very much.