Its the charging method used on ni cads that are different.
I think that only some old charges can charge Ni mih and i remember A Tekin was one of them. It was the top of the range one.
If it charges in pure Linear it will be fine. Flex is a big No No. The Delta peak is another problem as they are a lot lower for Ni Mih. This is why it was so expensive to update to Ni Mih as you really need to change charger.
If you spent big money on packs why would not get a charger for them as you can pick on up a lot cheaper these days. .. Its not worth the risk..