Embedding maps in Omeka sites

Hello, I hope it’s OK to ask a question about Omeka.org before setting up the site? Our team is hoping to set up an Omeka.org site (we have an Omeka.net one currently). I’m currently going through our project wish-list and wanted to check that it is possible to embed an ArcGIS Online map into a simple page on an Omeka.org site? I am sure it must be possible, but I tried on our existing Omeka.net site and it didn’t seem to work. Does anyone know the reason for this, and if so does the same reason apply to the .org site? It worked when I tested it in Wordpress using the same code.
Thanks in advance!

Could you post up the code that you used on the WP site? It sounds like either a WP shortcode, or a snippet of HTML. If HTML, we might be able to get around it with the security settings on an omeka.org installation