This is an issue that seems to persist even to the mighty Revit 2012. For [wall] face based light fixtures, annotation symbols do not display. And yes, specifically those in families from the Lighting Fixtures family. You can verify this by editing the family of one of those receptacles, changing it to a lighting fixture, reloading it and watching it vanish before your very eyes.
All of base fixtures I create employ an embedded Detail Item, as you mentioned - most of these are show at true size anyway. Now for devices that require a scalable annotation symbol, such as exit signs, I was forces to make them as floor or ceiling face based directionally.
I thought that might work when I was originally creating the families, but when I tried to insert the annotation symbol into the front view, I received a "Warning: Can't create this kind of element in this view in the current mode." message. Detail Items can be inserted into this view, but not generic annotations. Those can only be placed parallel to the Ref. Level, still true in 2012.
Symbolic Lines placed in the front/back view will definitely show up on floor plans and ceiling plans. However, these symbols are not annotative and do not have a size based off of the scale of the current view.
Our company specifically needs certain fixtures (exit signs and battery EM lights) to be annotative in this manner. We often create small scale plans for life safety drawings and if we have a building at a smaller scale than 1/16th, there is no prayer of making out the symbol. I even tried changing the devices to Generic Models, but that category behaves the same way, so I faked them as Lighting Devices, which failed for scheduling.
We once created subcategories for common scales within the embedded Detail Item annotation so we could manually control their size. Worked, but it was cumbersome.
Have you got your families available to look at?
Sure. I have three families of exit signs (all based on our company standard), Top-Bracket (for ceilings), End-Bracket (walls), Rear-Bracket (walls). Attached is the Rear-Bracket family as an example, as it is populated with Shared Parameters. It's a bit over-detailed, but does the job well.
BTW - It has been converted to Revit 2012.
Thanks CADastrophe - llok forward to looking at them. Was actually meaning though for jpriester to upload as was just thinking of a things causing the problem but wanted to see the family before commenting.
Was thinking it may be way family was created as wall lights (sconces) should be built differently to normal fittings so that annotation symbols can be shown in plan.
Thanks everyone for their input. Sorry I didn't respond sooner, but I was having issues logging in. Attached is a wall mounted exit light that just has detail lines drawn in the back elevation to represent our symbol for an exit light. Unfortunately, it is not annotative, and from what I read cannot be.