DateTime variable and IStringMap

[ssimop]

I am in need to build an IStringMap structure, with key computer time. I understand that it is only strings that this structure may accommodate. Therefore, how should I convert :

x.FromComputerTime

to store it in IStringMap and have structure sorted by time.

I have tried storing :

_s=x

the correct DateTime value is stored and sorted by I failed in finding a way to convert this string back to DateTime.

Any advice is mostly appreciated.