I am writing my thesis, and I want to auto caption my figures.

Because there are always some figures under the same topic, I wants to
number them as Figure 1-1(a), Figure 1-1(b)....Figure 1-2, Figure
1-3(a), Figure 1-3 (b)...., where first 1 is the chapter number, 1(a),
1(b), 2, 3(a), 3(b) ..... is the figure number in this chapter.

I tried to to it by right-click figures,>caption>numbering, tick
include chapter number, but word will automatically count my figure
1-1(b) as figure 2.

I am using word 2003.