For 1st season, find euroseededteams.csv at \Game\dlc\dlc_FootballCompEng\dlc\FootballCompEng\data and replace ids with teams you want to include in competitions.
For next seasons, inside compdata folder you have settings.txt.
Search (ctrl+F): info_special_team_id,393
copy/paste the whole line underneath and replace the id by id of added teams.
there are two places where you have to do that, the other one is a little further down the page and is for europa league
I have done everything you posted and I saved/replaced the previous existed file euroseededteams.csv. I also regenerated via both FHL-BH-Editor & C.M.'14 & saved all the changes.
Do I have to do anything else in order to have these specific teams from the 1st Season in Career Mode ?
can you help me please? I replaced Eredivisie with Greek League. All ok but in replays Eredivisie logo appears. How can I edit this to create a greek one, where can I find the prototype Eredivisie to edit?