Change permalink to look good

Hi there,
I have a question:
I want my permalinks to look like this:

• Frontpage: site.com/community
• Question: site.com/community/%category%/%post_name% (eg. site.com/community/general-question/change-permalinks)
• Answer: site.com/community/%category%/%post_name%/answer-%answer_id% (eg. site.com/community/general-question/change-permalinks/answer-1)
• Category: site.com/community/%category%

At the moment this is completely crap:

 community/question

is set in question permalink, because if I set “community” only, this leads to a 404 error

• Frontpage: site.com/community (but site.com/community/question when you click on breadcrumb)
• Question: site.com/community/question/%category%/%post_name%
• Answer: site.com/kb/dwqa-answer/answer-for-%post_name% (because in /kb/ is my knowledge base, but why is it used for answers?)
• Category: site.com/community/question/community?taxonomy=dwqa-question_category&dwqa-question_category=%category% (leads to a 404 error)

So you can see, none of the links work as they should

• On frontpage, the link sometimes contains the slug of the question permalink
• On questions page if would need to specify the same slug as the frontpage template
• The answers link is completely wrong
• The category does also contain the slug of the question permalink

How can I solve that?
Thank you
Zoker