Hi,
this is a known issue with the RTM Version of the html based SSP.
There has been an update that fixes exactly this issue (link), but as you will see under the Update Details it is already replaced by the second update for the Portal (see below).
This is the case, because those Portal updates are cumulative, so you Need only the most recent one.
Here the link to it:
Update (KB3134286) for Microsoft System Center Service Manager 2012 R2 Self Service Portal
You will see the install instructions in the link. Nothing fancy. Do a iisreset afterwards.
Hope this helps. Regards,
Stoyan (Please take a moment to "Vote as Helpful" and/or "Mark as Answer" where applicable. This helps the community, keeps the forums tidy, and recognizes useful contributions. Thanks!)