How will you say, "I dont know"

[Quest]

Hi all: Please help me.

Here is the scenario:
A potencial employer is calling up regarding an opening in their company. In the middle of the telephonic interview, the interviewer is asking, "Do you know to write for XXXX". And this skill, XXXX is not your area of specilisation. How will you express this to the potencial employer. You might be interested in focussing in other area of specilisation, which might be needed for the company.

Thanks in advance.
Quest

[Casiopea]

Hello Quest.

What about?

I'm interested in the opportunity; however, I specialize in Y and Z. Would those skills transfer over well? / Are there openings in those areas?

A little grammar and spelling help
A potential employer is calling up regarding an opening in their company. In the middle of the telephone interview the interviewer asks, "Do you know how to write for X", and X is not your area of specialization. How would you express to the potential employer that you are interested in working for them but in other specialized areas.