I would actually suggest a more direct way, instead of sending the documents you already have and then paying a second time to have them shipped back.
Instead of shipping your diploma and required documents for authentication from Peru to Spain, have your university in Spain send these (original copies) to the Taiwanese office in charge in Spain. After the process is done there, you can then arrange for DHL or other to pick up the documents and ship them to you. Keep in mind, there might be processes in between, depending on the country so this is where you have to plan accordingly with the Taiwan Office in Spain.
My case was possible because my university allowed me to pay online the fees concerning the issuance of a new diploma and transcript and then they themselves notarized it. Then sent it to the Taiwan office for final authentication.
Keep in mind that it could be different, just like in my case, depending on the country. It goes like this:
University issues and notarizes(through an on campus notary public) the diploma and transcript and then sends these to…
the Bezirksregierung or District Government (in the case of Germany) with jurisdiction of the region where your university is who then does a second authentication of the document and then sends these to…
the Taiwan office in charge of doing the final authentication for usage in Taiwan.
Another thing to keep in mind, and this is very important in your case, @lufrco you might have to do an extra step, something that the person with the Australian diploma didn’t have to worry about, and that is translation. Universities in Taiwan require the documents to be authenticated and all, and IF the documents are not in English, they have to likewise be translated into either Chinese or English. I say this because your documents are probably in Spanish and you most likely will have to do that.
This is where things might get a bit tricky. It is the same parallel process for the translations. Basically, I had to:
Translate diploma/transcript from German to English at an official translator, then…
Have the translations be notarized/authenticated at the Landesgericht or District Court where the translator is registered, then…
Take the translations, along with the (already authenticated by the Bezirksregierung) original diploma and transcript to the Taiwan office and then the process is finished.
Although this was the process in Germany, it is very similar in most countries in that it involves the original diploma/transcript being notarized/authenticated, then authenticated again at a government institution with jurisdiction in the region where your university is and then at the Taiwan Office. I hope this is of any help to you. Good luck with the process.