It seems like you using very old version of Easyblog, can you provide us with your Joomla backend and FTP access so I can help you update to latest version of Easyblog and help you setup that character limit?
By the way, in the future you can just include your site's access once at http://stackideas.com/dashboard/site rather than needing to keep adding them in your replies
I'm using Easyblog 5.0.13 et the latest version is 5.0.31 so it's not a very old one.
Pactes Conseil is not the only site of yours using Easyblog so I give you the back-end access here:
url = http://www.pactes-conseil.com/administrator
id = stackideas
pwd = 9wU8hJ+G6E)8nB(n2[d
Your version installed is .13 and the latest is .31. You are probably about 18 versions behind and there are actually quite a number of fixes on the latest version. Can I update EasyBlog to the latest version for your site?
I have updated EasyBlog to the latest version for your site pactes-conseil.com. As I am unsure what truncation settings you want, you could follow the guide which Arlex provided above
P/S: Please take note that support for Community versions are for 1 domain only.
Thanks for the update but despite of it, the field "maximum length of blog content truncated as introtext" (with default value = 50 characters) is still missing on my side.