Add separator to HelpMenu

Hi there,

i am adding a single action entry for my plugin to the HelpMenu (as this is only one entry, adding a group for it doesn't seem to make sense).

Is there a way to add a separator before my entry, without putting the entry into a group?
Or can a group be configured to not add a sub-menu popup, but have its actions listed directly within the parent menu?

thanks in advance for any hints on this,

Kay