How to EXTEND imported component styled components - reactjs

Question

I cannot extend my imported component. I was looking into styled components docs and find that in v4+ should works prop "as", but it doesnt.
COMPONENT:
type Props = {
padding: string,
justify: string
}
const FlexContainer = styled.div<Props>`
padding: ${props => props.padding};
display: flex;
flex-wrap: wrap;
justify-content: ${props => props.justify};
`
export const Flexcontainer: React.FC<Props> = props =>{
return (
<FlexContainer padding={props.padding} justify={props.justify}>
{props.children}
</FlexContainer>
)
}
EXTENDED STYLE:
import { Flexcontainer } from '../../reusable/FlexContainer';
const FlexContainerExtended = styled.div`
color: red;
`
USE:
<FlexContainerExtended
padding={null}
justify={"flex-start"}
as={Flexcontainer}>

Answer 1

You just have to add a prop className to your Flexcontainer component like this:
export const Flexcontainer: React.FC<Props> = props =>{
return (
<FlexContainer className={props.className} padding={props.padding} justify={props.justify} >
{props.children}
</FlexContainer>
)}
To override styles, styled-components passes a className as props to the overrided component, it's why

Answer 2

You can just pass the base component to the styled function to override it.
type Props = {
padding: string,
justify: string
}
const FlexContainer = styled.div<Props>`
padding: ${props => props.padding};
display: flex;
flex-wrap: wrap;
justify-content: ${props => props.justify};
`
const FlexContainerExtended = styled(FlexContainer)`
color: red;
`
export const Flexcontainer: React.FC<Props> = props =>{
return (
<FlexContainer padding={props.padding} justify={props.justify}>
{props.children}
</FlexContainer>
)
}
// And use it like this
<FlexContainerExtended
padding={null}
justify={"flex-start"}/>

Answer 3

I know this question was asked a long time ago, but I leave here the solution I found for future visitors.
Base component definition
import React from 'react'
import styled from 'styled-components'
const ContainerWrapper = styled.div`
width: 100%;
max-width: 1200px;
padding-left: 5%;
padding-right: 5%;
margin-left: auto;
margin-right: auto;
`
export default function Container({ children, ...props }) {
return (
<ContainerWrapper {...props}>
{children}
</ContainerWrapper>
)
}
Extended component definition
Obs.: note that the extended component is an article, while the base component is a div, and so far they have no relationship.
Also note that the base component (Container) has been imported but not yet used.
import React from 'react'
import styled from 'styled-components'
import Container from '../../common/Container'
const HeroWrapper = styled.article`
height: 100vh;
padding-top: 74px;
background-repeat: no-repeat;
background-position: center;
background-size: cover;
background-attachment: fixed;
`
Invoking componentes
Now, in the same file where I declared the extended component, I just call the base component, informing the name of the extended component in the as attribute.
export default function PostsWrapper() {
return (
<Container as={HeroWrapper}>
{/* ... */}
</Container>
)
}