Hello Antonio,
You mentioned html and Open Office and that's what I use to embed a PowerPoint into Moodle but I don't use a plugin. I needed a method that did not require modifying php files or anything on the server.
Here's how I embed a PowerPoint:
Create a folder on the desktop. This is where all of the files will be stored.
In Open Office open your PowerPoint file and Save As (another name to keep your original file in tact), File, Export as html ( "html" -there are other options but this is the one I use).
These are the other options I select or de-select (untick) when going through the series of pages:
New design - next
Sandard HTML format
I untick the create title page and show notes. - next
Save graphics as png
Medium resolution 800 x 600
No effects - next
Choose buttons - next
Apply color scheme from document - next
Create.
Name html design - no
Go to the desktop and open your folder, look for your file name with the extension .html. Open it and take a look at the results. I compress the folder and upload it to Moodle, now unzip, go to the folder and click on the html file again. When you do this, copy the the URL. Go to the page you are creating, let's say Compose a webpage, in the html editor embed this code and insert your URL:
<object width="700" height="600" align="middle" data="YouMoodlePageURLGoesHere">
</object>
I've used this method in Lessons, Compose a webpage, and on Online Text assignments. It worked like a charm until recently…I had my first conversion that did not transfer correctly. The graphics were out of place. Other than that though, it' really neat! And, just a few days ago I tested it on the iPad and it works very well.
The only drawback is that if you need to revise the PowerPoint, you have to repeat the process. This is the reason I came to take a look to see what the alternatives are.
I hope this is helpful.
Terry