Adapting pvc to cast iron combo.

[2hotntx]

Working on sister's old house. I'm attempting to replace sewer in her house and have run into big problem. There is a 4" cast iron combo standing straight up with what appears to be a 4" malleable lead pipe sticking out of the top and connecting to commode flange. I am replacing toilet and flange and would like to use 4" pvc from flange to combo. The 4"(lead pipe?) coming out of top of combo is bent almost in two about 3" above combo. What do I need to do? Please help!

[LazyPup]

I appologize for the delay in replying but to be honest I am having difficult mentally visualizing the layout here and there are a number of code issues that would apply.

Would it be possible for you to post a photo or a diagram of your layout?