Yes - this is a crummy feature of the integration between SSRS and SharePoint. Fortunately, your timing is excellent, as John Welch has posted a blog on this very topic in the last two weeks and has a nice workaround for it.
The link to the blog posting is here: agilebi.com/.../...sharepoint-integrated-mode.aspx
It requires you to create a custom permission level, but he outlines the steps quite well.