This comes up so often I guess you are already aware of the difficulties sending stuff over there. But I'll repeat my experience anyway.
We support an orphanage in the Central Highlands. We used to regularly ship clothing and other items but about 4 or 5 years ago the government started to tax these items heavily. Typically 400kg of clothing would be hit with duty of over £1000. At about the same time shipping costs increased from about £400 to over £1000. It simply wasn't worth sending things.
To be honest I've also had second thoughts about the rights and wrongs of shipping items that can be bought over there. We now try and buy local as much as possible. We employ ladies to make clothes for the children rather than sending from the UK. This has helped the local economy no end and allows these women to support their families.
We do make the most of our baggage allowance when we visit but its really been better for everyone since we stopped shipping stuff.