Format checkbox output

Dear Takayuki-san! I have a small problem with your plugin, I hope you can help me to solve it!
How can I format checkbox information output for the email?..
I mean… on my website a have checkboxes at the registration form for different events people would like to attend. They are listed one in a line with checkboxes like this:
Event 1
Event 2
…
Event N

But in e-mail all these events are in one line like this: Event1, Event2, … EventN
For my customer it is really difficult to have them in a one line but I couldn’t find any way to make them formatted one in a line again… Tags and special symbols are not working… is there any secret?…

Thank you in advance!

Orlanda

The page I need help with: [log in to see the link]