Edit mapping in CRM 2013/2015

How to do a custom field mapping in CRM 2013/2015

Hi,
I have been doing some more customization of Quote products and Sales Orders products  entities in CRM 2015.
There have been several fields added, so of course we needed to map these fields. In CRM 2011 we had a workaround for mapping in the hidden relationships and it was based on this article: http://dynamicslollipops.blogspot.cz/2011/07/mscrm-2011-mapping-opportunity-product.html

Now with the new versions of CRM we tested that it is still working.
I was not able to use the URL taken from existing views in the CRM system, but the old URL still works, so even in the new version of CRM we can use link in this format:

https://CRM/tools/systemcustomization/relationships/mappings/mappingList.aspx?mappingId=%7bXXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX7d

I just noted, that when I search for the relationshipid with this link SERVER URL/XRMServices/2011/OrganizationData.svc/EntityMapSet() I could not user Internet Explorer 11, because it was trying to get some feeds from there. So I had to use Chrome.

I hope this will be helpful,
Michal