Hey Angelic,
First of all, thank you for purchasing compojoomComment and supporting the component!
Let us say that you want to import comments from jomcomment.
Jomcomment is also placing comments under joomlaarticles and here is the key. If we import the jomcomment comments into compojoomcomment - then the contentids will be right ones. In both cases - you only use com_content.
Now in the case with wordpress - if the ids are different, then you won't get the desired result. The idea behind this wordpress import was the following. If I have a wordpress blog and I want to move everything to joomla, then I will move my articles to joomla and those articles will have the same ids as in wordpress.
You need to have the same ids. This is how this works and you won't be able to get the desired result if the wordpress articles and joomla articles have wrong ids.
I don't know how many comments and articles you are importing.
But if they are not a lot you could do a manual mapping.
So let us say that you know the following thing: the id of the article in wordpress and the id of the article in joomla.
You could go to phpmyadmin and write the following query
UPDATE jos_comment SET contentid = "you write here the joomla id"
WHERE contentid = "you write here the wordpress id";
I only hope that you don't have 100 articles and 10000 comments
Cheers