Since I am unable to post links I will copy my tutorial from the thread which I was referring to (not the set skin thread).
So the code which you will need to put into the dat1 file in your solution and the binaryData file named "EmbeddedData_GhostShipCXML" which is the first binaryData file should look similar to the one below.
Code:
<Object type="0x2202" id="Example Huntress Skin">
<Class>Equipment</Class>
<Item/>
<AnimatedTexture>
<File>playerskins</File>
<Index>92</Index>
</AnimatedTexture>
<SlotType>10</SlotType>
<Description>Example.</Description>
<Activate skinType="8705">UnlockSkin</Activate>
<Consumable/>
<BagType>1</BagType>
<DisplayId>Example Skin</DisplayId>
</Object>
For now you can put any string of digits into the "skinType" section (This will be revisited later). Once you have added that to your dat1 file in your solution and the 1st binaryData file then you need to add another XML which should similar to the one below. You will need to add this XML into the dat1 file in your solution, the 1st binaryData file and the binaryData file named "EmbeddedData_SkinsCXML" which is the 42nd binaryData file.
Code:
<Object type="0x2201" id="Example Huntress">
<Skin/>
<Class>Skin</Class>
<AnimatedTexture>
<File>playerskins</File>
<Index>92</Index>
</AnimatedTexture>
<PlayerClassType>0x0322</PlayerClassType>
<UnlockSpecial>Example.</UnlockSpecial>
<DisplayId>Example Huntress</DisplayId>
</Object>
Make sure your PlayerClassType matches to the class you want the skin to be for. Once you have added both XMLs into each file specified then you will need to save the binaryData files and replace them in JPEXS as well as rebuild your solution. Once you have rebuilt your solution you will need to open XAMPP and start MySQL. Next, open up HeidiSQL and navigate to any character's skin cell then enter in the Object type for the 2nd XML (0x2201) you have added, into any of the skin cells; this will convert your Object type into the string of digits you need to put into the "skinType" section of the first XML. Go back into your dat1 file in your solution and replace the skinType with what HeidiSQL showed you, do this for the 1st binaryData file as well. Save your client and rebuild your solution and your skin should now appear and work.
You can check out T's tutorial on client modification if you need to for further info on the client stuff.