Hello everybody! We want to start an ICO and we are interested of how to charge the investors with mosaic tokens in proportion to the invested funds? For example, Investors send BTC/ETH/XRP/XEM… and we need to give them our mosaic tokens, how to do that automatically? I know, there are special smart contracts, but how to do it in NEM?
You need to code that using the NEM API direclty or one of the frameworks/libraries.
It’s really not complicated though. You just create the namespace for your tokens then create mosaics. You can do that part from Nano (the nem wallet).
After that you just watch the your accounts on their respective blockchains and when a new tx hits you use the API to send mosaics to whatever nem account they registered (probably through a message in their tx on the original blockchain).
There is no fancy x-blockchain feature in nem yet so you gotta do it yourself but it’s no magic. Any half decent coder should be able write this up in a few days. The nem part probably in a few hours since the API is very straigh-forward.
Thank you, could you adivse somebody who can do it? Or may be, where can I find him?
If you want to run an ICO I’m assuming you have some kind of business going. Hiring any developer will do 
There are plenty on this forum so if you have an offer to make feel free to post it.