Wonderful post, Bodhigirl!
I want to address this question, with some suggestions. Yes, anger is threatening to who we think we are, based on conditioning. Anger is particularly threatening to the self-image of TMSrs who tend to see themselves as "good and in control."
The recordings on the TMS Recovery Program are a good intro to what it is like to explore anger with a skilled helper. It can help a lot to have coaching/counseling/support. Some in these fields can support you in this, others cannot.
A friend told me today that she enjoys rageful screaming when she is in the car. The automobile can be a very soundproof environment to express yourself. Having privacy is important. Expressing out in nature can be helpful. Nature can "take our energy."
Part of the way a helper invokes more experience is by prompting with words. You can do the same thing yourself in a safe place. Write out some statements which begin to "play" with anger. "I am so angry at you for not letting me be myself, Mom. Back off!!" etc. If you start yelling some of these things most likely one of two things will happen: There will be a natural willingness and energy to keep going and feel what you're saying, or the Inner Critic will arrive and try to shut you down. If the Inner Critic arrives, then you have more information about what blocks you from feeling/expressing. The messages about why it is not OK to feel anger become more apparent.
As Bodhigirl suggests, it is a process, futuredancer, and your continued practice, and your intention open the way. Just asking yourself to feel more allows less repression/suppression, in my opinion. Also, Dr. Sarno said that he only saw one patient express the primal rage which he posited is behind much of the TMS. He said "use your imagination" to discover what the emotions might be, based on your knowledge of the situation. So, while an expression of your anger might bring relief, it might be best to not get attached to the idea that this must happen in order to get relief. Good luck!
Andy B