Susan's Place Transgender Resources

I have been seeing a woman since late march, or early april..
We met thru a social network (not facebook) where I have
a female profile. I bluntly state on that profile that I  am...
Transgender, MtF, And ready to find a Dr/Therapist to start
hormone replacement therapy.
She and I talked a bit, she found out I was new to the Lake
area, and offered to show me around. I still present as male
alot of the time, but I'm ready to start dressing female full time.
   problem is, I stay at her place almost full time now & she
still has not approached the FACT that I'm Trans with her
12 year old son who she has full time.
   Her son and I get along great. I have been told by her that
I'm one of only a few people she's brought around that he has
not had an issue with,
   Her son has p.t.s.t. along with a few other issues due to
abuse, and mistreatment by his biological father. And therefor
he has Lots of trust issues with men.
   Seeing as I only look like a guy, but am a woman, I think he
subconsciously can tell, and therefor see's me as a non threat.
       (i've wondered off my point, damn a.d.d...)
  Anyway, This lady would like to approach the subject of my
being transgender, My impending transition, and the fact that
I soon will be dressing as fem full time.
however, She has NO IDEA how to approach the subject with
her son, especially since he has the issues that he does. She
Does not want him to lose respect for me, or to start having
meltdowns around me, or to start talking down to me like he
has with others in the past. ..

So, now to my question for you... (finally)

Do any of you have any experience in this area?

Any suggestions?

Any good websites I can refer her to, for ways to approach this
subject with her son?

Any help, or words of encouragement will be appreciated..

And thank you in advance.. <3 ~Madi~