what claycad said is very true, sad, and frustrating. it's hard. it's really hard. People who have never felt that steady thumping unending rollcall of suicidal thoughts just don't get it. It's not something people can fathom or truly empathize with if they've never been there. Not to be overly dramatic or ridiculous or anything, but I tend to think of it sort of like how a sighted person cannot and never will be able to understand what it is to be blind. The idea, to the average individual, of actually wanting to die is something near unfathomable. The human survival instinct is ridiculously strong...even when we don't want it anymore. Most Western societies inculcate us from a very young age to believe that suicide is wrong. Or to feel that it is inherently selfish and cowardly.
I've been there. Had people I care about, who care about me, turn their faces away when faced with the topic of suicide. It seems cruel and utterly unfair, but it takes time and a great deal of patience on your part before some people, even very good and compassionate people, can even begin to understand. People often feel hurt and frightened and react badly. Their first instinct is often to feel injured and offended, because being told that you want to die makes them feel as if you are telling them that they have failed. Suicide, even thoughts of suicide, can feel like the most painful sort of reprimand. Because it is an indication of such deep unhappiness, an unfathomable void that they, as your loved one have failed to fill. It hurts them. It is not your fault for carrying that void nor theirs really for being angry that they cannot fill it. They react as they do out of fear and frustration and backward indoctrination, and they react so because they love you.
If she still refuses to speak to you, it might be helpful to sit down and take some time and write a letter. Even if it is just an opening to try to get her to sit down and talk. Try to explain what you're feeling. Explain that the impulses aren't some sort of hoax you've taken on to deliberately and cruelly manipulate her. She may feel like you are just trying to get attention like a four year old. Often attention is, in a way, a big part of what we cutters or suicides are looking for. Not attention for attentions sake, but to be seen when we cannot shake off the feeling of invisibility, maybe to be saved, maybe to get the chance to say goodbye, or maybe to know that you are not the only one who knows. Sometimes just knowing someone else knows can help you go on. Thats one of the reason this site helps some people. Unfortunately, people who haven't even been down the road of suicide aren't always ready or able to help with the burden. It scares them and they run. It takes an unusually strong and compassionate person to bear upon beneath it and stand their ground. And I've babbled on here for a awhile, but essentially, I can empathize and can only say, don't blame your friend, don't blame yourself and just try to hold on.