convert utc/gmt internal time

we building c# concentration web-service client. run windows xp pc's.

one fields returned web use datetime field. server advantage domain gmt format i.e. "z" during end.

however, found .net seems kind excellent reworking always 12 hours out.

the following formula illustration resolves border 12 hour inadequacy left nonetheless creates stipend nz illumination saving.

cultureinfo ci = new cultureinfo("en-nz");
string date = "web use date".tostring("r", ci);
datetime converteddate = datetime.parse(date);

as per :

utc/gmt homogeneous

standard zone: utc/gmt +12 hours

illumination saving time: +1 hour

tide section offset: utc/gmt +13 hours

how adjust additional hour? finished programmatically kind sourroundings pc's?

code1