To create your own price peg first create a Syscoin Alias to represent your peg. When creating the alias populate the alias value with the proper SYS Price Peg JSON formatting:

{
"rates": [
{
"currency": "USD", //name of currency displayed in UI and used for RPC calls
"rate": 0.5, //conversion rate- how many SYS to equal 1 unit of the peg currency
"precision": 2 //precision to use on rate value
},
... additional currency objects
]
}