Updating a plugin for extra functionality

[leefish]

Hi, I am a small time user of mybb and a frantic hacker of plugins to tweak them to my specifications  (oh sorry, I thought this was plugin users anonymous....)

Anyway, I got a great plug in from the mybb site (it was for 1.2 but I changed it about a bit) and another neat FREE plugin from mybb central.

The two plugins are:

Threads on calendar (1.2 updated to 1.4/1.6) - this adds a table to the calendar view. When you view the calendar in day view you get a list of threads made on that day and you can click through to the thread.

Link to threads on calendar in action on my site

Mini Calendar on Index (updated to 1.6 and edited to show on portal).
The mini calendar shows events and birthdays from the main calendar. If you click on a date where the date is in red or green font  (birthday or event) then it takes you to the day view.

My master plan is to edit the threads on calendar plug in so that it changes in TWO ways.

1) Set which forums are chosen so that threads from private forums are not added to the the default calendar

2) automatically adds an event IF there are threads posted on that day (or does NOT create an event if there are no threads posted that day). That way when a user views the mini calendar they will see the days that threads are posted marked as events. Then they can click through and maybe wander about the site a bit.

I know that the MYBB calendar is perceived as pretty useless, but I thought this would be a neat way to add another access point to areas of the forum and try and use that big chunk of functionality.

Unfortunately I do not know how to make adding the event bit work. If I post the plugins here can someone maybe help?

Also, BOTH plugins are "do what you want, just leave my credits in" licences. As the original authors are retired/gone from the community I can't contact them to help me out :/